There’s also the fact that the original novelties, and therefore the original marketing materials, featured pieces of the official Witcher TV show logo, which might even be trademarked.
Plus, setting aside legal concerns, there’s also the problem of pi**ing off a major player in the entertainment business (Netflix). I’m sure GMK would like to be able to do officially licensed sets in the future, and running a high-profile knock-off (legal or not) doesn’t exactly endear you to future potential licensors.
Note that by “knock-off,” I’m not commenting on the quality of the hypothetical keyset. I’m sure it would have been great. But it still would have been unauthorized Witcher merchandise.