Yes, PC gaming has always been a bit of an anomaly in some ways - it just goes to show that market forces are more powerful, and more complex, than just who has the best equipment. It's all just the same VHS vs. Betamax issue, repeated ad nausium.
I think the biggest force which made the PC a success was its open nature, but now that games are becoming such a big industry, the tide has turned rather and it seems that closed-platform consoles are taking the lead. I guess that now the industry is big enough to drive big innovation due to competition, whereas before it was easier to innovate in "small chunks" on the PC (sound cards, graphics cards, etc.).
It's interesting watching these trends - I just hope that PC gaming doesn't die off totally, because consoles are such a limited environment that it seems very hard to come up with games with any degree of depth to them. Lack of keyboard and mouse, for example, are quite a barrier to certain gaming styles. Also, the "loss leader" approach of current consoles makes home-grown games much harder to imagine, because the console vendors charge awful licencing fees to studios (well, Sony do anyway, I've no idea about Microsoft - Nintendo might not be so bad, because they're smart enough to actually make a profit on each console unit).