If I grant you $1,000,000 in RSUs, vesting over 1000 years, is your annual income $1,000,000 ? No, it's $1,000.
Generally what happens is a laddering of grants. 100k over 4 years. Then a year later, another 100k grant. Then again the 3rd year. And again the 4 year. Once you hit that 5th year, you are indeed seeing 100k in stock each year.
Remember kids, stock prices don't always go up. Some stock prices go down, and sometimes all stock prices go down together. Those RSUs that, if fully vested, would have a market price of $400k at time of hire, may well be worth anything from $0 to $millions at the time they actually vest.
Yes, it is possible that you will be given additional grants or options repricing if your company's stock price declines. Usually not, unless you're a key employee or top performer, but maybe. But that doesn't mean the price won't just keep going down anyway. To say nothing of the bonuses and raises you won't get, or the mandatory across-the-board 10% pay cuts, or the elimination of all the miscellaneous perks. At least, unlike the employees of many of the companies I named above, you won't have a pension you can lose too.
I know it's hard to believe. Intellectually, you can look at history and accept, know very well, that most of these companies will fail someday, and many of them probably in the very near future. But viscerally, you can't get it, because they feel invincible right now. But they aren't. Believe it[0].
[0] https://en.wikipedia.org/wiki/Braniff_%281983%E2%80%931990%2...