I think the point is that RSUs are preferable if the stock goes up, and cash is preferable if the stock goes down. If the stock stays flat, there is no difference between RSU/cash split.

I think most people's assumption that the market will go up over time so most people would prefer RSUs. How accurate that assumption is in the short-medium term remains to be seen.

To be more general, RSUs are preferable if the stock goes up higher relative to other investments that the grantee could have picked, and cash is preferable if the stock performs worse than other investments that the grantee could have picked. For example, if the stock rises but performs worse than an index fund, then the grantee would have been better served to have gotten cash and put it into a no-effort index fund. If the grantee has an aptitude for stock picking, the balance sways even more towards cash being preferable.

Not true, because the cash would be distributed over time (as increased salary or bonus) as well, not a lump sum up front available for investment.

Still true if the investment made with the cash distributed over time performs better than the RSUs granted lump sum up front.

And yet if you look at most tech stocks that "halved" this year (which, btw, is an overstatement for most), they're still up from 2 years ago. My company's stock is down 25% but my RSUs that vested this year were still worth a hell of a lot more than when they were granted 2,3, or 4 years ago.