The inverse of that is already happening, although some die hard platform loyalists would be rather loathe to admit it.
Take a game like Batman. Development costs exceed $20Million, the majority of this is asset and content creation, licensing and promotional expenses. The actual coding of the game, while a very real cost, isn't close to the largest factor. Because of this, a game like Batman can be ported from the consoles to the PC and the potential lower sales aren't a major concern as you only need to worry about recovering the costs to port the game, not the more expensive elements which the console ports will handle the costs of. If a game such as Batman ran $1Million to port, sales of 300K units would make the game quite profitable, while it would need to sell closer to 1Million copies if it was an exclusive(which the console ports both will). Batman is just a singular example, but it holds up across ports in general, because publishers can use the consoles to cover major costs, the PC port becomes far more attractive as the porting costs give you a much, much lower sales requirement to get in to the black.
Yes, extremely. The i7 still can't fully emulate the EE used in the PS2, to emulate Cell you are looking at probably more then a decade out. A big part of it is 'endianess', but the consoles also tend to have CPUs that have considerably more FP power then comparable PC era CPUs(Cell still has more then double the FP power of the latest i7, after several years). That doesn't mean they are overall better CPUs by any stretch of the imagination, but it does mean that they are exceptionally difficult to emulate.