> Stainless steel rebar is a thing. It's expensive […]

That's an understatement. Fiberglass (GFRP) tops out at roughly US$ 2.50/foot, while SS can get up to $9:

* https://www.wellcoindustries.com/the-cost-of-rebar-and-the-c...

The low-end of plain steel rebar is $0.40.

There's also Glass Fiber Reinforced Polymer rebar but I don't know much about costs and how good it is vs stainless steel rebar.

> Stainless steel costs much more, but total project cost goes up less than 10%.

I think people are often surprised how little materials cost affects the total cost of a job.

I'm having this argument at work, where I want some more expensive cabling installed in a bunch of offices across Scotland so it doesn't need to be done again in another ten year's time, but "that stuff is so expensive, do we really need it?" is what I'm running up against.

So as it turns out today I'm giving them a breakdown of the cost of the job. Guess what the expensive bits are?

Did you guess "wages for two guys, hotel rooms for two guys, 800 miles of diesel, and a couple of ferry tickets?"

Well, you're way ahead of today's crowd then.

> Two piers were built in the 1940s, side by side

As far as I can tell, only one pier was built (using stainless steel rebar) and the presentation is comparing it to a hypothetical alternative as a theoretical exercise: "What if the Progreso Pier was built using carbon steel rebar?"