Would it have really made a difference? Inter-company collaborations always end up with one company becoming dependent or the other buying them out, or both. Vaio would have become synonymous with Mac OS until Apple ditched them and left them to the same fate as they currently face.
Apple's problem was the other clone manufacturers undercutting them. Sony is a company that is known for being willing to charge premium prices for their premium products. It may have worked out.
I'm not sure it would have made much of a difference though.
I am thinking commoditization of the entire device is flawed while commoditization of parts is not. The way people think they can buy a PC for cheaper than the price of its parts is probably a good example.
It's interesting to see where Apple has done visible product collaborations before. Rarely have they been effective. In the post-clone (Jobs.2) era I can recall the HP-iPod [1], and the Motorola RAZR with iTunes [2]. Both (differently) lopsided in their loyalties. Both failures.
In an alternate version of history, It may have been possible for Apple and Sony to seal the relationship and may be co-operate on iPhones and iPad, possibly slowing down Samsung Juggernaut. Well.. you never know...
