FMMonty do you remember the Stac Electronics case? It exemplifies the problem with Microsoft.
Stac created a diskcompression program for DOS/Windows called Stacker.
Digital Research went to them and licenced it for DR DOS.
IBM went to them and licensed it for PC DOS.
Microsoft went to them and attempted to dictate terms that were destructive to Stac. Stac said no. Microsoft created a competitor that violated patents held by Stac. Stac warned them of the violation and were blown off. Stac took them to court for patent violation. Microsoft was forced by the court to remove the program, they did and created a new version that did not violate the patents (no problem with that). When they released the new version they also changed DOS so that Stacker could not be loaded with the old method. The new method was undocumented and the EULA included a clause forbidding reverse engineering. Stac reverse engineered it anyhow. Microsoft sued and the EULA was held to be invalid in that area. Stac won. Stac does not exist any more. Who really won?
This is an exact example of unacceptable practice, so you'd think. However what Stac did is purchase a software patent from a British company called Ferranti and used that patent to sue Microsoft. Patent 4,701,475. This is common in software these days, since patent fishing works very well.
You also didn't mention that Stac lost the reverse engineering case and had to pay Microsoft 13.7 Million for illegally ripping off their doublespace preloading system, or that they had been given an advance copy of the new DOS 6, allowing them to prepare their product for the changes that were taking place.
Yes Microsoft did try to destroy Stac, however what actually destroyed them was cheap harddrives, and the fact that every operating system had bundled disc compression (MS were the last company to do so).
By changing DOS to remove the ability of Stac to load their program Microsoft violated anti-trust laws. Microsoft by changing DOS and putting that EULA clause in was eliminating the ability of Stac to sell their product to 90% of the market so that Microsoft could control that market. Microsoft didn't win by making a better product. They won by using the control of the dominant OS to block a competitor from being in the market. They won by forcing that smaller competitor to expend their profits in court rather than on legitimate competition.
Microsoft didn't change DOS and refuse to allow Stac to reverse engineer their product, they countersued stac for using thousands of lines of Microsoft code, and won.
The ability to do that to a competitor makes Microsoft a monopoly under the law. Doing it makes it an abusive monopoly and guilty of illegal acts.
When Microsoft says you can't sell our products if you sell our competitors product that is a violation of the law. When Microsoft says if you sell our competitors product you must still pay us (making the competitors cost artificially high and non competitive) they violate the law. They have done both of these and been ordered by the courts to not do so because it is an illegal abuse of a monopoly position.
People often sign exclusive deals to get better prices. However I agree that it is harmful to your competition to say if you sell bobs you can't sell ours. Why should Microsoft want to encourage competition?
This Marxist idea that we should regulate businesses to stop them being successful is silly.