Assuming it works perfectly, speech still couldn't possibly be the main way to use a computer:
- hearing people next to you speaking to the computer would be tiring and annoying. Though remote work might be a partial solution to this
- hello voice extinction after days of using a computer :-)
Oh, yeah, I mean, it would've been awful had it actually happened, even if it worked properly. But try telling that to Microsoft's marketing department circa 1998.
(MS had a bit of a fetish for alternate interfaces at the time; before voice they spent a few years desperately trying to make Windows for Pen Computing a thing).
This is _always_ the problem with these things. Voice transcription was a great tech demo in the 1990s (remember DragonDictate?), and there was much hype for a couple of years that, by the early noughties, speech would be the main way that people use computes. In the real world, 30 years on, it has finally reached the point where you might be able to use it for things provided that accuracy doesn't matter at all.