In late 1980s, it was expected that by 2000, you'd have a GaAs computer on every desktop (powered by Occam or Prolog, of course ;-)). In the end, it turned out that silicon had more life in it than was expected, while being much cheaper and easier to manufacture.
Re:Making the new silicon
by yakshemash on Thursday July 30, 2015 @11:27AM
(#9975649)
There was also the fact that silicon was already heavily entrenched in the industry by the time people started to tinker with the possibilities of GaAs seriously. At least that's what I understood to be the main factor after listening to Seymour Cray's talk which was posted here some time ago:
https://www.youtube.com/watch?v=xW7j2ipE2Ck
He talks about how difficult it was to convince large suppliers to work with GaAs at about 30 minutes into the talk.
Not exactly sure why the tech is not more widely used though. Funnily enough, most of the GaN and GaAs devices in general use are LEDs!