Not like a Microsoft, more like an IBM?
I would think the comparison would be better if it were made against a hardware manufacturer. AWS is IaaS - the key being Infrastructure, not SaaS or PaaS.
As such, the comparisons aren't the same any more. The accusations against Microsoft are that they force you to do things their way, use their software, and tie you into all things Windows. I would argue that AWS is more like there being one supplier of 90% of the PCs in the world - you can put all sorts of software on them, use them in a much more varied way.
Granted there is still a sort of lock-in, but the lock-in is only with the hardware that they are virtualising, and we are almost all using that in the non-cloud world.
The only companies they might put out of business are those that offer infrastructure related products. Amazon won't be writing Office type applications, but they will be offering more things that make it easier for people to build SaaS products on their service.