FYI: The rule with FireWire, as with any other electrical transmission, is that signal loss is proportional to length of cable. This is inevitable. WIth FireWire and USB, the loss is much less noticeable, since all signals are digital. So, the signal will hafta degrade a WHOLE LOT for the receiver to pick up a 1 as a 0.
As for the multiple cables of component video - this is just pure speculation - but it might have been done to decrease manufacturing costs. Think about it, the computer VGA standard was made since there wasn't anything that could handle its signals before. RCA cables already have adequate bandwidth for component video, since resolution is only bumped up maybe 4x, to 1080i at most. So, having to create entirely new assembly lines and dies for a new transmission system wouldn't be good business, if you could just order more of the same stuff e.g. 3 CA connections.
FireWire promised it would be incorporated into VCRs, DVD players, TVs, Dolby receivers, and everything else that has a power plug right when it came out. The possibilities with computer hookups were, i think, just not seen back then. This i.Link HDTV connection stuff coming out now was what FireWire's creators wanted from the beginning for their dear little plug.
But, I don't think it'll totally take over RCA stuff, since RCA connections are too firmly etched in the electronics industry. It would be like Xbox trying to compete with PS2 (I have an Xbox, BTW). It'll never catch up, unless it can offer something revolutionary and 30 times better, since it has no installed base, whereas RCA connections are found in every single piece of A/V electronics in your living room/family room/bedroom.
I think FireWire will, in the long run, either hafta improve a LOT (a.k.a FireWire2, FireWire3) or it'll stay like it is now: a cable to serve your iMac, iPod, and digicam.