> At the time they merely shipped the browser with the OS.
> They were also accused of adding new features only in IE which forced websites to deal with incompatible browsers
I do not think this is an accurate representation of history.
First, Microsoft was fighting against the whole concept of a browser as separate from its OS. The fact that one can 'change your default browser', as you so casually say, without changing your OS was a major victory in itself that people worked very hard to ensure.
Second, it was not just 'features' that Microsoft added to IE. They were actively ignoring standards and with Frontpage people could easily generate web pages that looked fine in IE but were a complete mess of impenetrable HTML for other browsers. And when you complained about this the owner would simply add a 'best viewed in IE' icon on their website and start blaming you instead...
In short, at the time it was not at all obvious that a large majority of the web would remain accessible using any other browser than IE. (And similarly for email clients, by the way.) I agree with you that there is still plenty of shady behavior going on, but I am not sure that I would classify the old practices as 'fairly benign'.