MS managed the fruits of the SoftImage acquisition pretty poorly. It had a lot of potential, particularly since MS could have parlayed it into a part of the premiere games development platform, but they bobbled it pretty badly and ended up with trueSpace instead, which has really never come even close to living up to its potential.

Autodesk and Adobe compete really only in digital audio & video editing, and compositing. The rest of Adobe doesn't really have much impact on any of Autodesk's businesses.

I suspect that Autodesk bought Alias for Alias:Studio rather than for Maya, because Alias:Studio is the Big Dog revenue stream there, and among Autocad's biggest competitors.