For example if a 25 yr old coder is $X per year surely, even if you have terrible age discrimination, there must be some salary level, say $0.75*X where having the older worker is preferable?
Is it that older workers are much more expensive and are bidding themselves out the market? Is it that people value youth so much they will pay a 3x markup for it or something?
If there's a large pool of super skilled people begging for work I don't quite understand why someone wouldn't want to leverage that. I get why maybe you pay older workers less if you discriminate, but to not hire them at all seems strange.