I do partly agree with you, but there are still some fundamental things going on in Silicon Valley. On-line education, I think, has the potential to be very transformative. Self-driving electric cars could also have a very positive effect on the world as well (including solving the "last mile" problem with train travel). There's also a lot going on of course with bioengineering, and while I wouldn't necessarily equate this with silicon valley, Stanford, Berkeley, and UCSF are of course highly relevant research institutions. And let's not discount the advances in distributed computing in making all of the above possible, some of which did come from silicon valley companies.

Of course, just because these things may greatly improve the quality of life doesn't mean that they'll create jobs. They may destroy them, and while so far people have found new industries and jobs to replace the ones that become obsolete, I suppose there's no guarantee this will continue to be the case in the future.