I think it's getting harder and harder to justify. Especially given what mid-career devs at these companies are earning. $150-200k base plus 100k/yr or more in stock after a few years, that's far cry from 90k + 0.1% of some junky seed company with about a 1% chance of IPO.

If you look at my comment history you'll see I've been saying this for a while and I think it'll only get more true with further industry consolidation, which will make it both harder to displace incumbents product-wise, and harder to compete with them salary-wise.