Former Vole Joachim Kempin, who was VP of Windows Sales at Microsoft for 20 years starting in 1983, made the claim in an interview with IGN.
He said that Sony was always at arm's length with Microsoft, but Vole wanted them as a chum because there were a lot of things they could have cooperated on.
Kempin said that Sony bought Windows for their PCs but when you really take a hard look at that, they were never Microsoft's friend. Vole wanted them to be a friend because they knew they had a lot of things they could have co-operated on because they are, in a way, an entertainment company. Although not very entertaining.
As soon as Sony came out with a video console, Microsoft just looked at that and said "well, we have to beat them, so let's do our own".
According to IGN, the move came from the top of the company, with Sir Bill Gates putting his oar in. Gates was not really a fan of consoles because he was worried that a living room computer would metamorphosise into an alternative PC that could threaten Microsoft's dominance of the traditional market.
As a result, it was eventually felt the company had to try and tackle Sony head-on and come up with a product of its own so if there was any metamorphosis then Microsoft would be the one turning into a butterfly.
The only downside was that both Vole and Sony were losing a bundle on hardware and needed to make shedloads on software to make a profit.
Kempin said that he went to several PC manufacturers and tried to beg them to do the Xbox thing and keep the device manufacturing out of Microsoft, but they were not stupid enough to bite.
Kempin claims Microsoft never really managed to nail the whole software-supplementation thing, with Halo ending up as the only exclusive software franchise they could depend upon. They came up with a few ideas and managed to break even. But in the end they have effectively neutered Sony which was the goal.