It's pretty obvious that PS3 would be comfortably in second place (assuming the Wii remained unchanged). That's not fanboy speak simply the most likely outcome.
Without the year start, particularly in the US market, 360 wouldn't have had the time to win over enough marketshare and developers would have gravitated immediately to the PS3 assuming it would be the winning platform, leaving the 360 with the ports rather than vice versa as happened.
I think 360 would still have done well vs Xbox once Halo 3 launched but I have zero doubt it would have started and stayed behind the PS3.
MS pushed very hard to be first to market, to get a good SDK into developers hands to make DVD the standard physical limit for most title, and for a very good reason - they knew they had to otherwise they ran the risk of only seeing a modest increase over Xbox from the previous generation.
Try to be reasonable... its easier than you think...
