Most late employees got generous RSU's instead of options.

Only to employees hired post IPO though, correct?

Why would it be restricted to post-IPO employees? It's pretty common to get RSU grants at a startup pre- or post-IPO. Typically you can negotiate the mix.

Source: have received and negotiated on offers within the last three years from "name-brand" pre-IPO startups.

No, they've been granting private RSUs for at least a year before.

I don't know where they can get their figures. $15 sounds a bit high for a median. The average tho is in the S-1: $2.33. Maybe the average is heavily skewed downwards by some very cheap penny options?

I have to believe it’s heavily skewed with older huge grants to higher ups

Large portions of these grants are likely to be in the form of RSUs rather than options. I find the whole "underwater" narrative less compelling for this reason (RSUs are never under water).

But presumably the employee had to pay a load of taxes on the RSU, no? I don't think SNAP is down so much yet, but you could end up with a very large loss, which is difficult to write off if you don't have other capital gains. Yes?