Do you have any data that top talent tends to value equity higher than salary? All the smart guys I know favor the latter. Too many companies use it as a tool to trick the less intelligent guys that they'll make bookoo bucks despite being given a joke amount of equity. Plus, you as an engineer rely upon your C team and potential investors to be competent enough to not screw things up. I also live in a state with lower taxes, which could be part of it, and a weak startup scene.

Equity will cost you at least 25% in taxes, should you get something out of it and needs to be accounted for. Additionally, you need either a lot of equity or a large exit to come out ahead of a higher salary that allows you to invest the difference, netting you at least a 5% return normally. On top of that, if you have 401k matching based on salary percentage contributed, you'll net a larger 401k, which is even more money. Further, to get that equity you have to remain at most places for 4 years, which seems to be pretty atypical nowadays.

If someone offered non-trivial amount of equity for a lesser salary that is a completely different scenario.

I've ran the numbers for a startup that just made me an offer and it is pretty absurd how much smarter a larger salary would be at a 200 million or smaller exit.