Historically, the solid pay and good prospects have been a primary driving criterion for people going into engineering. The Silicon Valley idealists who want to "change the world with food delivery" is the new phenomenon, not the other way around.
> The Silicon Valley idealists who want to "change the world with food delivery" is the new phenomenon
The Silicon Valley idealists who want to "change the world with food delivery" are (as a broad class, not every specific instance) largely PR faces created for marketing purposes by and for people who want to make lots of money, and know that having some kind of compelling mission (even if that "compelling mission" might change to something radically different later on) is important both for attracting customers and for attracting investors.
I mean, I don't want to mock it--it's challenging stuff, and makes a lot of money. It's the optimism that's a total culture shock to me. What I consider the traditional engineering attitude is the exact opposite--conservative, pessimistic, "don't fix it if it ain't broken."