Actually, there was about a 15-year period where many people didn't think PCs were good for anything, because they had access to much better (shared) computers. That's the context where http://catb.org/jargon/html/B/bitty-box.html comes from. See also http://canonical.org/~kragen/tao-of-programming.html#book8. Throughout the 01980s PC Magazine worked hard to convince business decisionmakers that IBM PCs weren't merely game machines; if you look at old issues you'll see that computer games were completely missing from the abundant advertisements in the magazine, presumably due to an explicit policy decision.

I personally encountered people arguing that using PCs (as opposed to VAXen or mainframes) was a waste of time as late as 01992. And I actually even sort of joined them; although I'd been using PCs since before the IBM PC, once I got access to the internet in 01992, I pretty much stopped using PCs as anything but a terminal or a game machine for years, spending virtually 100% of my computer time on VMS or Ultrix. When I was using PCs again, it was because I could run BSD/386 and Linux on them, in 01994.

(Maybe you'd assume from my own story of enthusiastic adoption that "nobody ever sat in countless meetings asking[,] "How can we use the internet?"', but if so, you'd be extremely wrong. In 01992 and even in 01994 there were lots of people who thought the internet was a fad. Bill Gates's The Road Ahead, published November 01995, barely mentioned the internet, instead treating it as a sort of failed experiment that would be supplanted by the Information Superhighway. Metcalfe predicted in 01996 that it would collapse.)

It can be easy looking back in retrospect to oversimplify events like these with the benefit of hindsight, imagining that the things that seem obvious now were obvious then. But not only weren't they obvious—in many cases, they could have turned out differently. I think it was Alan Kay that argued that, without the invention of the sort of graphical user interface used by most non-cellphone personal computers today, the personal computer as we know it never would have become a mass-market phenomenon (though video game consoles were) and therefore Moore's Law would have stalled out decades ago. I'm not sure he was right, but it seems like a plausible alternate history to me.

Of course, there were "killer apps" as early as VisiCalc for the Apple ][. Accountants and corporate executives were willing to read through the manual and take the time to learn how to use it, because it was such a powerful tool for what they were doing. But it was designed for specialists; it's not a UI that rewards casual use the way Excel or MacPaint or NCSA Mosaic is. Without the GUI, or if the GUI had come much later, plausibly personal computers would have remained a niche hobbyist thing for much longer, while somebody like Nintendo would have locked down the unwashed-masses platform—as we now see happening with Android. And (maybe this is obvious) that would have made it immensely less useful.

Microsoft’s original source code