Why are there no tube televisions anymore?

My point is no matter the technological advances audio will always begin and end with electromechanical interfaces and video with electro optical. 

Well, when I brought home an AQ Niagara power conditioner to audition in my Stereo I decided it was a keeper.  I had been using a Furman Elite 15 PF i power conditioner.  What to do-so  I put the Furman in the Home Theater system which has a few months old Sony XBR LCD TV.  The Furman made a striking difference.  The colors on the TV are much richer now.  I marvel at the picture every time I watch TV now.  I use some mid level AQ HDMI cables but do mostly streaming these days.  (4k blu ray easily outshines 4k streaming btw) I had thought about a better power conditioner for the home theater but was not as motivated to spend the money like I do on the stereo system.
About tube TVs:  Some reminiscing about the late 1960s.  My dad brought home a Philco 25" color TV in the late 60's.  It had the best picture that I can recall on any TV until 4k.  For real.  I can remember seeing Star Trek on that TV in the late 60s.  I noted to myself a year or two ago that it was not until these 4k TV's came along and the original Star Trek series was remastered in HD did the picture finally look better than on that Philco TV.  It took nearly 50 years to get a better picture.  Remember, Cable TV had the worst picture.  It might have looked clear but it was grainy due to overdriven signals.  Then TV's got bigger but the resolution stayed behind.  The only downside was that Philco TV ate tubes.  I remember often going down to the drug store to test tubes because the picture would either lose its color or go out completely.

Remember the Quasar, "works in a drawer" TV's?  They had a literal slide out cabinet with the circuit boards in a row like files.  I recall reliability was poor due to the bad connectors at the base of the boards.  So ironically, easy to work on which was good since they needed servicing often.  The good old days- AM tube radios, car tires that lasted 5000 miles, oil changes every 1500-3000 miles, carburetors (good luck starting on cold mornings) but also we had soda fountains, juke boxes and roller skating rinks.  Real movie theaters...

Sound is created through mechanical actions, ie. vibrations. Audio begins with the microphone and ends with the speaker. Everything in between matters but is not seen. Same with video: it begins with light and ends with light. Everything in between matters but is unseen. Wow! Must have been that cheesecake last night.

I love my eye popping colors and razor sharp 4k picture. That’s part of the entertainment. If I want realistic colors and contrast I’ll walk outside. And another thing- you can buy a $500 pair of speakers with perfectly flat frequency response and a $500 receiver with top rate THD specs and wide frequency response. Set them up in a hemianechoic room so that you have no reflections and standing waves. On paper it is the perfect stereo; in real life it is completely useless.  I know.  I tried that once. 

So out of curiosity I changed my picture setting on my TV to Cinema.  I find I like the picture better on this setting.  Live and learn.