This is what unions are all about - most people should limit the allocation to their job, but a lot of employers (not just Musk) want employees to work "like owners" without providing real ownership of the equity upside of the company they work for. Even most equity packages do not provide upside on a remotely similar scale (you might make 500k extra) compared to what the founders, execs, and VCs will make on your labor. I'm not sure that HN is going to be very Marx-friendly but Capital Vol 1 gets into this if you can hang through all the blathering about coats and fabric.