Re: "GPL is cancer"
The bad, fragmented GUI and bad tools the other reason, yet that could have tech solutions - what stops many companies is incurring in license issues, and there is no tech solution there, but a big effort to replace all the GPL libraries with something else. And if for any reason you need kernel modules, you're even in a worse situation. Stallman & C. won't go after small developers breaking the GPL - but if a large company with a lot of cash does, they will go after it.
People will pay for it when they are the people used to pay for the same software on other OS. Evidently you won't target the actual 5% which is mostly made by activists (let's exclude some developers, especially web ones) who don't want to pay for software. But professional users have no issue in paying for software, and they could move to another OS as long as they find the same ecosystem they're used to.
GPL with all its ideological strict limitations ensures they won't. And Microsoft thinks "thank you".