Most of that is equity comp for engineers.

For government you have to factor in job security, generous pension and benefits, and guaranteed annual pay raises.

Engineers have none of those things.

Not small if you consider total govt. employees in SF.

The link that showed the 90 employees making $300K or over is a link to a page about San Francisco city employees specifically, and says there's 40,951 total. (And it is 90 exactly according to that page.) So is 0.2% of workers earning that much a lot compared to tech companies, do you think?

How about employees making $200K or over? That's 1790, or just about 4%. $100K or over? 15997 employees, or around 39%. So over 60% of SF city employees make under $100K. The median salary, in fact, is just under $86K.

I could be wrong, but I suspect that's lower than Facebook's median salary.

Pension, overtime, benefits, job security.