> they depend on a bunch of Microsoft proprietary extensions

Microsoft still holds the crown when it comes to C# debugging, but for most proprietary MS extensions there are free, open source alternatives. They may not be as polished as the ones Microsoft actually pays people to maintain, but I don't see why Cursor would actually depend on any of the proprietary ones if you're not using it for C# dev (and even there competitors like Jetbrains have figured out a way to make it work).

And hopefully Cursor can give some funding to the FOSS alternatives