Lesson: don't do one-off projects. Find a project that meets you needs, and copy it. Make minor tweaks to their design to fit your needs, but copy as much as possible.

Houses typically go according to plan because so many of the processes and parts are standard. Even large mansions can go according to plan if you have good management (note that cheap management is rewarded for change orders and thus will ensure things don't go according to plan while better management will see that if they don't make a minor change now things won't go according to plan latter.

Imo big infrastructure needs like roads and subways shouldn't be done on a project basis at all. For instance, NYC shouldn't bid and build out massive contracts for a few km of subway. They should own a boring machine and add 10-100m of tunnels a week, every week[0]. (numbers arbitrary) You can shake so much overhead around project start-up and shut-down and it will be a long time before NYC (nevermind someplace like SF) has saturated the demand for public transit.

[0] Best example of this sort of logic that I have seen implemented is painting the golden gate bridge, just one properly sized and experienced crew painting from one end to the other and back again without the boondoggle.

I've thought the same for a while. A lot of the expense in upgrading rail cars, replacing frigates, building hospitals etc comes from the fact that every such project has massively expensive organisation constructed around it and then ... it's thrown away.

The Project Production Institute take a similar view: that instead of modeling a project as a fixed thing, you focus on it as a production process.

https://projectproduction.org/

But why there is a need to paint it all the time?

To make up some numbers: Assume that a paint job lasts 20 years. So if it takes a team of five 20 years to paint the bridge by the time they've reached the end the beginning will need a new coat.

Otherwise every 20 years they would need to hire, train, then fire 200 painters for a 6 month-long paint job project. 200 painters, managers, and etc. who will invariably be less experienced with the finer points of painting said bridge since they don't do it every day.

So it doesn’t rust

Most houses are unavoidably one-off projects. The point of comparison would be an assembly line at a factory. Compared to that, most houses are one-offs; that particular design has never been built at that particular site by that particular group of people and contractors.

Guess we should have stopped at the wheel.

We have improved it a lot, but the wheel has been round for a very long time. We laugh at people who reinvent the wheel as opposed to doing incremental improvements on it.

We do have ships, rockets, and a few other things that don't need wheels (tough they tend to have wheels of some form inside), but the wheel itself is still just incremental improvements on that first one way back...

NIH and 'reinventing the wheel' are phrases for questioning the need to spend time and money to develop a thing that has the same purpose as an existing thing and doesn't improve on it, which I agree with. But to use ships as an example, at some point people decided it would be useful to cross bodies of water without getting wet so they invented the boat, and as a new invention it improved quality of life immeasurably. It feels like you're saying people should exclusively stop making things which have new and novel purposes and just focus on improving existing things, which is the part I disagree with. Also, I think as an example, gears and wheels which have similar bases of design are two completely different inventions because they have different purposes, this might be where we disagree.