This isn’t the complete picture. It’s true that the vesting schedule gives you only 5% of RSUs in your first year, but employees’ cash signing bonus is increased to offset that. So if the total compensation target for a role is generally $500k (say, a principal engineer or a director, maybe?) and your salary is capped at $160k, you’d be given a signing bonus of $500k-$160k-(total stock vest x 5%) in cash. It’s not as though you’re paid significantly less when you start, it’s just that how you are paid is different.

they give you a signing bonus, paid out over time, to make up for the difference in total comp in the first two years