I see your point. And many a jealous DS would agree with you, off the record. However, I also see Sky as having a team that had a lot of momentum, from a psychological standpoint, this year. You would be amazed at how much further you can push yourself when riding on the front, as opposed to sitting 30 guys back, given the same physical condition. It's just a rule of thumb in cycling, better to cause yourself pain than have others cause it for you.
Now, of course, I can see you rolling your eyes thinking about the TdF's of the early 2000's and how similar my answers to doping questions are to those of a certain texan-belgian tandem in those days. So, as opposed to a psychological intangible, let me give you something more real:
Sky bought a whole crew of guys that would be outright leaders on any other team to be support riders. I do not see that as the case with USPS, with the exception of Heras. Remember Aczevedo finishing 5th at the Tour de France? Who? Yeah, exactly. While the comparison is visually compelling, the reality is not. I still think it;s unfair what Sky has done, but from the payroll perspective, not the doping one.