My understanding is that monopoly by itself is not illegal but it is the abuse of one’s market position in one thing to gain advantage in another. Not saying this is correct, just, or legal, just saying that’s what I think is how things are at least in the US.

If it wasn’t obvious: I anal.

What does open source have to do with choice?

As has always been the case, you can use whatever browser you want on whatever OS you want. This has never been more true than right now.

I don't think using the open-core model gets them off the hook.