I suspect the cause is the shift in how startups are viewed in Silicon Valley. Even though there've been startups here for a long time, they were always conside

I suspect the cause is the shift in how startups are viewed in Silicon Valley. Even though there've been startups here for a long time, they were always considered risky, marginal and low-status. So the supply of potential employees was low and the early payouts you're thinking of were paying people for taking a risk. Today startups are considered to be glamorous. They have access to a lot more investment and potential employees. The whole country seems to be making a beeline to pony up for the high rents because the salaries more than compensate for it. There's no longer much risk of lost earnings. Is it any surprise that the equity has gone lower? Arguably the valley as a whole has taken the deal suggested in OP: more salary, less equity.