That's quite true. I didn't see San Francisco till around 2000. But I have to say that all the talk about starving artists and such is really off base. Without Silicon Valley, San Francisco would just be another urban place with character like say, Seattle, Washington or Portland, Oregon. It has a decently developed culture for a US city. But it's nearness to Silicon Valley (and to a lesser extent Hollywood to the south) is what gives it notability beyond that.
From my point of view, what is special about Florence and Silicon Valley is the trade/industry. The Renaissance followed from that in Florence. It'll be interesting to see what follows from that in Silicon Valley. Already, we seem to have some significant stuff in space flight, for example.
Finally, I imagine that artists in Florence probably were complaining about the merchants, cloth finishers, and bankers too.