> but there's no mission and purpose behind, just making someone make big bucks. Quite the opposite in Sillicon Valley, I suppose, where one can build something that actually affects the world.

This is not universally true. One can find examples of SV companies that are not doing important things that affect the world (e.g., "Yo!") and one can find people on Wall Street who are making money and using it to affect the world (e.g., James Simons and the Simons Foundation).