I don't think so, browsers have always, until now, been able to set themselves as default, even back during the Netscape wars.
And they're not asserting ownership of your computer. What they've done is created a hamfisted (and biased towards Microsoft - yeah, I don't like it either) interface that replaces third parties modifying your computer with or without your consent. They had a better system in Windows 8.1, and should revert to that, but nonetheless, I don't actually like the idea of a browser being able to set itself up as default. I prefer myself to make that decision. Fortunately, the mainstream browsers have, until now, always at least asked for permission before changing the defaults, but that's not something they should have been allowed to do to begin with.
If we want this changed, we need to be a little less hyperbolic, because the issue here is that the new change isn't user friendly and is biased towards Microsoft, not ludicrous claims that Microsoft is taking control of your PC in some way it wasn't before. If you complain about the latter, expect your ticket to be closed with a "INVALID. Not actually a description of a real problem."