Agreed. Usually the console that sells the most is the lead platform (NES, SNES, PS1, PS2, Wii was too weak so Xbox 360 was lead platform)
I think the XB1 will be the lead platform for two reasons:
1) Xbox 360 was the leading HD console in sales for a majority of the generation and has huge mass appeal in NA and the UK. These are two major markets in the western part of the world (where the gaming audience has shifted to since the early 2000's). It would make sense to follow that up by having devs supporting the leading console (I realize the PS3 has taken over worldwide now).
But think about how many ports the PS3 got at the beginnning of the gen, all because the PS1 and PS2 were so dominant and publishers were expecting PS3 to follow suit (but it didn't take off as they planned). Then western devs quickly banked on the 360 as the lead platform (this was also due to PS3's cell architecture being difficult to master compared to 360's PC-like architecture). That's why you saw lot's of third party games and Unreal Engine 3 games coming out on Xbox 360 first (i.e. Mass Effect, Bioshock, Elder Scrolls IV, etc.)
2) The lowest powered console is usually the lead platform because it's easier to make a game run with minimum specs and then crank up the graphics and effects for the more powerful platforms. It's much more difficult to make a huge sexy game like FFXV and try to get it running on Wii U for example.
Now, this is also misleading because usually the lowest powered console is the highest selling, but if the PS4 takes off in sales and is selling twice as much as the XB1, you may see the PS4 as the lead platform, but most of the time the games will be identical as it's easier to port up instead of porting down.