What!!! You're kidding; the personal computer came of age in the '80s, particularly when IBM commoditized it by making the design of their PC public. With Microsoft offering their OS to anyone who wanted to install it, the PC-clone industry quickly rose to push out all competitors (including Apple). By the early '90s, everyone knew what a "PC" was -- an IBM-compatible computer running Windows. (And that's still true today -- e.g., even Apple has "Mac vs. PC" advertisements, when technically Macs are also personal computers...)

Apple survived only by inserting its products around the edges of the market; with the laptop segment, with boutique high-end PCs, by coming up with popular derivative gadgets (iPod, iPhone, iPad...). Even today, Apple still hasn't dared to go back into the traditional expandable desktop PC market (although I think they could get away with it if they tried).

But yeah, Apple has fought back, and in fact is still in the process of getting back into a fully mature market...