30% actually.
Just a few weeks ago, I tried playing a Japanese game that I was interested in, but it didn't even get past the start menu. Not a big deal for me as I'm not an avid gamer, I just moved on.
But imagine telling a hardcore gamer that no, you can't play that new game released an hour ago. Maybe it'll become compatible a few months later, maybe not.
Or tell a professional artist that no, they can't use that art software anymore, they have to retrain their entire skillset with an entirely different software.
Now that's a show-stopper. For most people, it's 100% compatibility or bust.