I am aware of the history, I had a read up in preparing some of these arguments.
Lets put aside the issue of monopoly, since it's not something I will subscribe to.
On the issue of them making a computer, I have seen rumours that the Surface RT will force you to use the MS provided browser, and that the EU may take exception to this. Do you therefore feel that this would be unfair? Unless of course the rules were applied uniformly, meaning Apple and Google had to allow the same level of competition.
Don't get me started on Software patents, which I would say hold back innovation far more than Microsoft have ever done.
I have built many PCs, for both domestic and business. Some Windows and some Linux. My website runs on a Linux box, as does my home server and netbook, my desktop on the otherhand is W7Pro/IE9 (With Chrome as a 2nd browser.) There is plenty of competition between operating systems, and OSX does quite nicely (If Apple would allow it to be run on any PC it would probably give Microsoft a much greater run for its money.) The thing is that Windows and OSX are both very user friendly at the expense of being able to perform detailed configuration and having access to very low level functions of the OS. Conversely Linux allows a much greater level of control at the expense of the user experience.
You talk in terms of specifications being stagnant, have you considered that stable may be a better word. While at home running the latest and greatest of everything is fine, if it doesn't work properly then it's annoying but not the end of the world. In business though, constantly changing specifications would be a nightmare that is best avoided.
I can't really argue with you on cost, I have to agree with the previous posters who comment on how the Lawyers do quite nicely on this. I would however recount something I once heard in a previous job. Comparing the cost of licensing W2k3 vs Red Hat Linux, Microsoft was considerably cheaper than Linux once support costs were considered.