> pissing away our society's resources on monuments to hubris

Is it impossible to imagine a cause that transcends vanity or hubris?

Must every collective effort be corrupted by selfishness?

Collective efforts directed to realizing the vision of the few are inherently suspect.

For that matter, what if a megaproject is required for a space faring race, and democracy is the great filter?

Or we could forget about the probe and focus on developing better propulsion technology. That would have immediate applications, but could also allow the probe to reach its destination orders of magnitude sooner.

I don’t see any reasonable motivation for generations-long megaprojects until technology has well and truly stagnated.

I posed Proxima Centauri simply b/c it wasn't religious, and perhaps palatable as something humanity should undertake, but not feasible within a lifetime, as a counter-example to show that not all lifetime-spanning projects are worthless.

If the Cold War was still raging and Russia decided -today- to colonise Mars, it'd immediately go from a "someday/maybe" to "within the next 5-10 years".

Even ignoring the hyperbole, this isn't accurate. It's only because of survivorship bias that we think of building standards as having decreased over time, but they really haven't. Take an average person from an average house 500 years ago and put them in modern construction and they would be amazed by how nice it is, how it's well-insulated and climate controlled, how smooth the walls are, how level the floors are, and even simple stuff like how the roof doesn't leak one bit when it rains.

There's going to be many more modern buildings still standing hundreds of years from now than there are buildings from hundreds of years ago still standing now (both in absolute numbers and proportionally).

Take your hypothetical person from a half millennium ago - yeah, they'd be amazed by how comfortable the house is, and all that... but they'd also likely be appalled by the level of maintenance required to maintain that, both in terms of the actual structure and the amount of work necessary to fund the ongoing use of things like air conditioning and electric lights. With that taken into account, we spend a good deal more of our lives providing ourselves with shelter.

Also, as part of that, there's the fact that the home of five hundred years ago was likely built with the most durable materials that were feasible for the time and budget. Today, even the most expensive homes are made of materials that explicitly will not stand the test of time. In fact, I'd go as far as to say that our culture values things that are more fragile and fleeting - a home with a beautiful bay window is a thrown rock away from being essentially uninhabitable until that window is replaced, at great expense. We delight in our ability to impact the world around us, and very rarely build things to last longer than they need to.

"they'd also likely be appalled by the level of maintenance required to maintain"

Modern materials have much lower maintenance requirements. You can put up a tar-asphalt roof and aluminum/vinyl siding and be fine for multiple decades without needing any maintenance whatsoever. Meanwhile, a lot of older houses needed extensive maintenance every year to keep the roofs and walls in passable shape. Wattle and daub was a common material used for walls, for example, and thatch a common material for roofs. Both are incredibly labor intensive to maintain.

"With that taken into account, we spend a good deal more of our lives providing ourselves with shelter."

Huh? How are you measuring this? The average person centuries ago lived at just barely subsistence level. They spent most of their efforts on basic survival, and sometimes didn't even have enough to eat. We spend much less of our lives laboring now than our ancestors used to. Compare how hard and long a subsistence farmer or serf works vs a modern office worker. It's much easier for us to provide shelter; we just spend some fraction of our salary on it.

"home of five hundred years ago was likely built with the most durable materials that were feasible for the time and budget"

Yeah, so only the palaces were built amazingly well and everything else was not. The living standards were so much lower back then that almost no one had the money to get access to the best available stuff, whereas nowadays most people do.

"a home with a beautiful bay window is a thrown rock away from being essentially uninhabitable until that window is replaced"

I don't even understand this criticism. The only way to not have this be a problem is to literally not have glass windows at all. Either you have an empty hole in your wall that's terrible for retaining warmth in cold weather and keeping out bugs and rain, or you don't have holes in your walls at all and live in darkness (both were common options). Would you seriously rather live in a house without windows??? To the extent that people didn't used to, it was only because glass was so expensive that the average person couldn't afford it. Now that we have modern production methods, glass is cheap, and everyone can benefit from it. I guarantee you that if you went back in time offering free glass, the average person would gleefully put it in their house. It was only used in palaces, cathedrals, and the like because of how expensive it was.

The average person 500 years ago lived in what you would call nowadays a ramshackle hut. I don't know what is coming into your mind, but you're probably thinking of one of the few well-made structures that persists to this day, rather than what was actually commonplace. Keep in mind that entire cities used to burn down too, which no longer happens in good part because of modern fireproofing codes and materials. Drywall, for instance, is an amazing material.

The overall idea that I'm trying to get across is that the best homes of today are not nearly as durable as the best homes of 500 years ago. The historical home would have had likely had stone walls if the owner could afford it, and a heavy timber-framed roof with lead or zinc overlaid for protection from the elements - exactly like Notre Dame, in fact. A modern home of the same cost (i.e., belonging to a person of equivalent economic class) is going to be much more comfortable but is much less likely to stand the test of time - at least, unless it substantial ongoing maintenance.

To put it another way, after a hundred years of abandonment, the historical home would likely still be standing. Barring extreme weather, the roof would likely be still in place. A modern home however would decay much more quickly, because of the assumptions that we make today about the availability of quality materials for repair and maintenance - and yes, because the materials to which we have access today allow architectural styles that were previously impossible, like huge bay windows.

Give people a choice between two houses, one that will last their full lifetime and then some, and another that costs double and that will last 500 years, almost everyone is rationally going to pick the former option. There simply isn't much present-day utility in over-building to such an extent.

And keep in mind, there are plenty of all-stone buildings that have collapsed from earthquakes and other natural disasters, killing many people, e.g. https://en.wikipedia.org/wiki/August_2016_Central_Italy_eart... . A lot of construction methodologies that last 500 years only do so in some environments. Against a lot of common risks, a modern building constructed of dimensional lumber is better.

And anyway, I still think the better comparison is between the average building in different time periods, not the best buildings (which are basically just outliers).