Say you make $150k. As far as I know that is around $100k after taxes i.e. $8350 a month. Say your rent is $4k and another ~$1k in miscellaneous expenses. That leaves you ~$3k in discretionary income and probably a bit less for saving if you want to have some "luxuries".
If you have been in the housing market for a long time or otherwise have a better situation your living expenses might be a lot lower. If you are paying $1.5k (upfront or de facto) in housing costs that might effectively double your savings i.e. what you get to actually control from your salary.
But it is sort of worse than that. Because every additional dollar you want to make gets taxed with your marginal tax rate. Meaning if you want to have the same savings as someone with lesser living costs you have to increase you salary quite a bit. In this case you have to go to somewhere close to $200k. Which is a pretty huge gap for something that doesn't have anything to do with your actual work performance.
Of course this can all get better or worse depending on circumstances. Still, it is a big deal.
Whilst the no-poach agreements were wrong, I don't think comp was kept artificially low in the way you mean. What drives up comp in the valley at the moment is the existence of companies that make tons of money but have voting, share structures and cultures that don't incentivise them to return any to investors. The combination of huge profits, endless vanity hiring and no dividends or share buybacks is fairly new and it's not clear to me it's a good trend. I don't believe Facebook, Google or Twitter actually need all those engineers they're hiring.
And yes, I think that'd be the right thing to do. The sums of money we're talking about here are vast. They're not going to go into the pockets of some stereotyped "fat cat" capitalist. Outside of pension payouts they'll be reallocated to other companies that may be doing important things of the sort that big internet firms just won't tackle, like biotech/drugs research.
Look at it like this. Does Google really need to create yet another instant messaging product for the seventh time? Or would the capital used to do that be better re-allocated to some other part of the economy?