Despite the fact that a polygot dev. with tons of experience is always good to have around, and you need some weighing in on big decisions ... most dev is just dev - and a competent mid-tier developer with good habits can do the job in most cases.
That said, I really wonder about management - a talented senior dev who can write clean code, is polygot and knows their way around everything, gives good estimates, communicates well ...
I think that might worth more than anything really.
Often tech is more like a sports team where individual contributors matter more than those making other decisions, i.e. coaches.
(That said, there could be a serious market inefficiency here: a spectacular coach may be worth more than great players, it's just really difficult to measure!)
People going into software should plan accordingly. You get great wages to start, but you need to save some of those for a potentially risky mid-career transition where you specialize in a particular subfield.
Well this would be the root of the problem right here, not "experience doesn't matter after 10 years." That's nonsense. Experienced people with in-depth, cross-functional knowledge obtained from several, 5-8yr "sub careers" in various specialties can be worth their weight in gold.
There's a lot of managerial things you continue to learn, but that requires you to be in a position with enough political capital to actually stop history from repeating itself. It's only useful knowing that Project X will fail, if you can convince people to instead do the more successful X++. I'd expect job title to be a much better indicator here: having 20 years of experience doesn't mean you have the aptitude or inclination to succeed at office politics.
To be a bit longer-winded:
If you want to get paid more, you have to demonstrate value. Even if you only ever write the same CRUD apps, you'll definitely improve for the first few years, and it makes sense to pay more for a developer who isn't still busy making their first mistakes.
Past a certain point, though, raw experience isn't automatically a value add. If you're still just writing the same CRUD apps, you cap out a certain point. Now you need to demonstrate that you can contribute to architectural discussions, get involved in system design, or help with project selection/management. If you think you deserve the big bucks for that level of highly experienced work, that's totally fair, but you need some way to demonstrate it - whether this be tiles held, references, or having literally written the book on the topic. You can't just lean on "years of experience" anymore, because it's no longer well-correlated to value-added.