Here's the insidious thing about these kinds of "bonuses:"
They take four years to vest. In that time, Apple can (and 100% will) dump any/all of those devs before those stock options are available, then work hard to attract younger engineers (who will accept smaller salaries than their predecessors for the boasting rights of working for the fruit) - and the stock options offered this year to all the engineers they 86 will become worthless, because they're contingent upon still being employed by Apple.
Every SV company does this: they dangle enticing fortunes in front of the grunts, with no intention of actually ever paying out. It looks festive and generous in the PR release, but in 3 and a half years, after everybody's forgotten about this, Apple will cut the cord on every single last one of them, and welch on the bonus stocks.