This blog explains why stereoscopic 3D is awesome and I concur...
https://pcper.com/2012/10/why-stereoscopic-3d-is-awesome/
The guy at my defunct local movie/CD store always said he agreed and that 3D looked better than 4K. And if your local DVD store geek guy isn't an expert than who is?!
I think it failed, however, because 3D isn't just about a crisp image or seeing into a world as I've often seen argued. You have always been able to see into a world with 3D. It's just a product of modern CGI filmmaking that the world we see into is more rich/complex. But 3D is about the old novelty... a world coming out of the screen towards you! I recently showed this to a 4 year old for the first time and can attest from his experience that is where the fun is at. When film makers that didn't make their films in 3D started having their films made to be 3D anyway, you can bet they didn't care about this at all!
Star Wars: The Last Jedi 3D Bluray Review
https://www.youtube.com/watch?v=JB8UX6-EBsI
Also, see comments at the link above to hear more 3D lovers say that they prefer it over the added pixels of 4K.
The other reason 3D failed is people hate paying extra at the theatre and at home, especially given the already outrageous prices. At the theatre you recycle the glasses for heaven's sake. The extra price makes no sense.
Long live 3D of all kinds!
