This boils down to software development not being free. In VLC's case, the development is funded by several for profit companies (like videolabs) that make their money from stuff they do with VLC (consulting, commercial services, etc.).
VLC is a good example of an OSS project that is pretty well run with decades of history that has a healthy ecosystem of people and companies earning their living supporting all that and a foundation to orchestrate the development. I don't think there ever was a lot of VC money they need to worry about. This is all organic growth and OSS working as it should.
So, this boils down to what paying customers of these companies are paying for. The project also accepts donations but those go to the foundation and not the companies. It's the companies that employ most of the developers. And you can't fault them on working on things that they value. If AI features is what they pay for then that is what they work on.
I happen to share your reservations about the UX. It's a bit old school, to put it mildy. And they obviously don't have professional designers that they work with. Like many OSS products, it looks and feels like product made by techies for techies. It doesn't bother me that much but I do notice these things. I actually talked to one of their IOS developers a few years ago. Pretty interesting person and not a huge team as I recall. I remember talking to her about some of the frustrations she had with the UX and the lack of appreciation of that. I think she moved to Netflix afterwards.
Like with most OSS projects you are welcome to take part in the meritocracy and push your favorite features or pay somebody to do that for you. But otherwise, you should just be grateful for this awesome thing existing and prospering.