The problem is not the capability of the chain but the enthusiasm and willingness of the community to do such a thing. The Ethereum and Alt-coin communities have taken a much more welcoming and open approach towards appreciating what is built on Ethereum. Ethereum also has an application centered approach. For most people, the idea of making an application is much fancier than the protocol level work that Bitcoin community values.
Yeah, I think this sums it up pretty well. Ethereum's primary use-case is creating tokens, so NFTs effectively enhance the utility of that environment. The benefits outweigh the costs there.
Bitcoin's primary use-case is (arguably, because I know there's always room for disagreement on this) censorship resistant and secure transfer of wealth. Anything not geared towards that goal is often perceived as a drain on valuable resources. It doesn't enhance utility. The costs outweigh the benefits here.
Totally different priorities.