I think the EU was right to do it, because they realised how important the web is. But we didn't really feel the effects. Normal people still used IE, until they didn't.
In the end, I think Microsoft brought the demise of IE on themselves, because of how terrible it was. They couldn't undo that reputation, not even with Edge, which still feels clunky compared to FF or Chrome.
So this example is ambiguous w.r.t. hands-off vs. hands-on regulation at best.
It was not only about the browser as such but a lot of APIs were connected to IE. I don't remember the details but on several projects I worked on you needed IE installed to do stuff that was unrelated to the browser.
Also, Gates's reputation took a big hit with his behavior during the Congress hearings.
All this together caused a lot of harm to MS's image which may not have happened without the DOJ and the EU going after them.
I also wonder if their investment in Apple was at least in part motivated by them being investigated. There may be no Apple today without that.