Many companies vest those RSUs monthly or at least quarterly, and for public companies employees can sell right away. This is a very common paradigm, and in fact financial advisors would frequently recommend employees sell all shares at vest to diversify.

I've worked at places also where 105b-1 plans were generally available (sell all shares at vest even outside trading windows), in which case employees were absolutely receiving 40k+ liquid cash a month. Many senior engineers were receiving substantial more than that.

Some companies vest quarterly with no cliff, so you are going to vest within 3 months of starting.

Before the stock declines, an experienced engineer could get offers for 40k a month before taxes. I didn't believe it till I tried. It's real. Amazon frontloads in cash, Facebook has 3 month vesting.

The cost to the company is the same, one just has better retention properties.

The last 3 companies I worked RSUs vested either quarterly or monthly and were then immediately liquid.