Re: "probably to avoid litigation with IBM"
Um, if I remember correctly, there was no chance of litigation since IBM did not bother to protect anything via copyright. It was a truly open market.
That's why IBM attempted a market takeover with the PS/2 when it realized how the market was shifting - except that it didn't work for various reasons, but mainly because there was no point, technically speaking.
Avoiding litigation with IBM concerning the PS/2 was definitely a concern, though, which is why the PS/2 is dead and the PC lives on.