I hardly think "owning stock" is the goal, rather than "receiving compensation". Vesting schedules that backload compensation to discourage quitting early are hostile to employees, and makes them feel unfairly "locked in" because they lose a disproportionate amount of their unvested compensation relative to the percentage of the vesting period that they have spent working.
By comparison, Facebook vesting is evenly spread across four years, with refreshers granted every year, so that people can expect to receive relatively stable compensation for as long as they stay at the company. There's no "bad" time to leave when it comes to your vesting schedule, so you don't feel "locked in" for anything beyond the total value that you'll always be leaving on the table, regardless of when you leave. Refreshers don't even have a vesting cliff anymore, so you don't even feel the need to stick around for a particularly good batch if you don't want to.
You're receiving an equivalent amount of cash. If you want to invest it, you can. If not, you're still getting a consistent amount of money for four years (or more if stock goes up).
"Give some of the money we pay you back to the company" vs. "here's some valuable securities which you can sell at some point in the near future when they are worth more than what you'd have paid for them".
By comparison, Facebook vesting is evenly spread across four years, with refreshers granted every year, so that people can expect to receive relatively stable compensation for as long as they stay at the company. There's no "bad" time to leave when it comes to your vesting schedule, so you don't feel "locked in" for anything beyond the total value that you'll always be leaving on the table, regardless of when you leave. Refreshers don't even have a vesting cliff anymore, so you don't even feel the need to stick around for a particularly good batch if you don't want to.