The problem with these really big TVs is that they are too big to watch normal day to day TV stuff and even at 75 inches they are not that immersive for 3D, even if they were 3D capable.

I like to use my projector when I want to be more like being at the cinema, without the volume being too loud and people squeezing past when they come in after the film has started or need to go to the toilet and without kids talking or eating noisy snacks.
That way it makes movie nights, especially in 3D, more special and I would love to go even bigger but my screen only gives me an 85 inch picture but with the lights out and the 3D glasses on you feel really immersed in the action

I hope that affordable 4K projectors with 3D are not too far off.
Optoma have a non 3D one coming out around June for just over £2000 so hopefully once the others catch up they will bring the prices down and add the 3D to them