You don't have to work at any of those places to earn a better deal than what these startups offer. I certainly don't work at those places, and it's unlikely I ever will for a variety of reasons, and I'd be taking a steep (> 15%) pay cut to work for $130K/yr. Compared with my current salary, any equity would have to be worth at least approximately $25K/yr (before any discounts against the lost income are applied, so it's a low figure). At 1.5% equity, that's a valuation of about $2M/yr for the startup. That's not a lot compared to the exits these companies may make, but it's not insubstantial, either, and is probably an aggressively optimistic estimate given the preference for investors, dilution, etc.