That sounds like some reductionist hackernews question that tries to hint at some clever insight but I'll assume no snark and answer with as much insight as I can.

You just make less of them. Some buildings are discretionary, like your big apartment buildings you probably want (these were the two that got cancelled).

Person funding can make x profit over building per year. Person loaning loans x for y sum. Building costing more than interest amortized profit means it doesn't get built.

And I just had a doctor's office fitout cancelled mid project (drafted it personally :) ). so apparently those are, too.

Public projects like schools rarely get cancelled. Factories I personally don't draft so I really can't tell you.

Healthcare absolutely has a ton of discretion for their buildouts.

What's the alternative to steel? You just make less if it's not profitable to make.