Yes indeed it has; but you said "fabulously rich", which is a more recent phenomenon.
If anything, from 1970 to late 1997 you did have a few differences - the fraction of scams dumped at inflated valuations on the public markets was a lot lower, and the number of huge company exits was lower - but that's actually more about how the industry was healthier (less bullshit) and smaller (it hadn't grown yet).
In other words, longer than Silicon Valley has actually been a thing (it used to be Santa Clara Valley!)
My dad did the startup thing in the 80's, and still has his old stock certificates representing a non-trivial ownership share. It didn't work out for him, but I tried 3 decades later with some measure of success. So this is at least two literal generations of Silicon Valley economic mobility here.