In my impression it really accelerated after the '08 financial crisis (+- a few years for all the people who left wall street and went to HBS) after being an ibanker was no longer cool or well paid and the people who would have gone there decided to come to Silicon Valley. That's a huge mass of people who are grinders who just want to make money and quick and have a totally different mindset than the people who wanted to build cool shit that solved their own and others problems. In my mind these are the people who did GSB/HBS, Google PM, failed at a startup that raised a bunch of money from their friends and network, and then became a VC. Not that these folks were all bad, they probably did help professionalize the tech industry and focus it on solving big problems (unfortunately imo that was overindexed on potential returns rather than potential positive impact) and brought huge amounts of capital to bear on the industry. But yeah, I left SF after the millionth pitch I heard of people who were going to build a world changing product and it ended up being on-demand laundry service or 10 minute grocery pickup while being in a city surrounded by homeless tent camps and people in such mental anguish that they would be screaming in the streets in broad daylight.