Exactly, there is no "engineering" separate from the beans.

Anyone can make a bridge that stands. It takes an engineer to make one that barely stands. The same largely goes for computer systems.

When the economy is booming and there's a lot of money sloshing around, developers can get away with shrugging and saying "not my problem" to things like cloud costs and energy efficiency.

Those same developers don't get to complain on the rainy day, when someone who knows how to save the company millions of dollars a year gets a better deal.

Engineer’s don’t build bridges that barely stand up, they have a huge margin at completion. Instead they build bridges based on some agreed upon lifespan.

They do make the cheapest thing counting that margin. Immediately past that margin of safety, your bridge will fall down. In other words, given an expected load of 10 tons and a 50 year lifetime (as you mentioned), an engineer will try to design the cheapest possible bridge that holds 50 tons (5x load) and will last 70 years.

Being able to handle 50 tons at year 70 may be well over 200 tons at year 1, which is a hell of a lot more than a simple 5x margin.

Sure. Pick a specified load at a specified time and the engineer's job is to build the cheapest possible bridge at that load and time. Raising the safety factor doesn't change the objective function. The objective function is still "cheapest within spec."

This is why bridges are not just huge chunks of titanium. Those would work very well at handling 50 tons at year 70, but would be shitty bridges because they are too expensive to build.

I agree that cost is a factor, but cheap is really only one of many factors being optimized. The actual cheapest design is often some organic looking design that comes out of software optimizer, but you lower risk by using proven designs.

Why do you lower risk by using proven designs?

Could it possibly be because it is cheaper to insure, repair, and work with those designs?

Risk is expensive. That's why you reduce it. If it weren't expensive, you would take it on.

> Why do you lower risk by using proven designs?

That’s not necessarily the risk being avoided. The customer may be better off, but project management’s risk vs reward looks very different than the customer’s risks and rewards. Get enough stakeholders together and …

So no, people really do regularly reject the cheapest design that fulfills the spec.

I'm not saying you should be completely ignorant of price, I'm saying use the standard parts and practices first, then worry about costs in revisions after you've built something. Premature optimization and so on. Maybe you can save money on a different powder coat color so you don't have to worry about skimping on parts or power conditioning or something like that. The project is usually bigger than the engineers little corner.

That's fair. Get something working > Doing it right/perfectly the first time, most of the time.

That being said, you should be able to have enough awareness to avoid anything particularly egregious - eg. avoid things that you would never want in a final product anyway in the first place. I guess we probably agree on that when you say standard parts etc.