I think you're jumping the gun a bit. While the physical disc market is obviously in decline, it's still significant. Oppo's problem wasn't so much that they made a UHD player, but that they made a $500+ UHD player. This is just a very small niche market. But other UHD players have been on sale for less than $100 recently.
Personally I'm sorry to see Oppo go. I don't have their UHD player, but I do have an older Blu-ray player (BDP-93) which is still going strong and doesn't just play 2D and 3D movies, but also DVD Audio and SACD. The build quality is excellent and their service is second to none.
I doubt that TV sets are going away anytime soon. As a data point, Netflix recently
disclosed that 70% of Netflix's streams are consumed on TVs.
I would never watch a movie on a phone. Actually, even TVs are too small; a projector with a 120+ inch screen is where it's at.