I agree, they were all once on equal footing, and now each has their own niche they fill (and yes, one or two may decide the direction of the NEXT Gen systems like Xbox and PS2 did). But I still side with the fact that all will still have a descent backing, and neither Nintendo, Sony, nor Microsoft is going to just "throw in the towel" with any of their systems after what they spent to release them. I mean, MS came out with the HDDVD addon just in time for the release of the PS3, I can see all of them competing like this for a little while, which is good, except maybe the Wii, I think it will sell well enough but will never be a real powerhouse.. Stiff competition is good motivation to make things better for the consumer.
I bet Sony is, right now, looking for ways to make the production of the PS3 cheaper so that they can get the $600 price tag down to compete with the 360. If not, they're friggin' idiots.
Edit: Yes, one could argue that they are all on different formats, and therefore it will be more expsensive to release say, the next Splinter Cell, on all 3 systems. In this sense I think Xbox has the upper hand, since its already established in the market.