Until you want to do something that "Just Can't Be Done", which is where the strengths of having a general-purpose computer that acts like a general-purpose computer come into play.
True, but I think it's a matter of the paths of least resistance.
Let's say there's a 80/20 split, between what is really easy or quick or fun --some subjective measure of "better"-- to do on the console vs what you need a general purpose computer for. At some point, the console is going to win out and those 20 percent items, and tasks that you'd need a general purpose computer for are going to somehow change. Either you'll find another way to accomplish the same general task or tools for the console will arrive that are "good enough". So the question would be, does the console do enough of what people generally do to change the things they rely on a general purpose computer for?
Granted, the successful consoles I can think of are all TV related, and the TV has key advantages over general purpose computers for those consoles (bigger screen, setup to be watched instead of worked on, better sound, etc).
