I think this is a great example (although tounge in cheek i expect!) of the difference between movie/TV and theatre and the difficulty of putting theatre on TV where people are expecting a more TV experience.
Watching it theatre on a TV means people compare it more to filmed things, and find it harder to suspend belief. We are so used to having snazzy special effects, cgi etc to support stories with massive sets that it makes look theatre look basic. You have to sort of switch your mind to be more focused on acting without all the flashy bits that are actually distracting and can ruin the heart of a story.
There's a couple of shows at the moment (harry potter, stranger things, back to the future) which have some really cool special effects/magical moments and its amazing seeing them infront of your eyes and knowing your own eyes saw it so its not cgi, theres a collective gasp in the audience and its genuinely shocking. I suspect it would look really underwhelming filmed, because we are so used to million dollar effects.
You would also probably be able to see how it is done watching it at home. All theatre isn't designed to be watched close up, but from the middle of the stalls/ people sat in row m 2 teirs away. Most of the costumes, facial expressions, voices, make up, emotions etc are designed to be seen from quite far away and not in a close up. You can't have the really subtle facial expressions you do in a film because it doesn't read past the front row. So if you aren't used to it, it can look odd.
The filming of stuff is amazing for access but I do think it loses the atmosphere and puts people expectations to be to watch a set filled, prop filled subtly acted in 300 takes type show rather than the raw, on the night buzzy show
A bit like if you listen to a live recording of an album vs the released , its more atmospheric with more raw vocals, where you might get more voice cracks and lose being able to hear the subtle piano line you love, vs being there in person and seeing it preformed live. They all have their place
And of course not everyone shares the same tastes, ask anyone about any adaptation and everyone will have a fight about the favourite of the book vs the movie or that the 3rd adaptation is shit but love the 2nd. Pride and prejudice is a great argument starter for this!