The biggest CRT ever made: Sony's PVM-4300

I'm kinda curious if CRT technology advanced to the point where a TV like that would've been possible at a better weight and price tag? I assume that CRT technology development stopped decades ago, but could we have e.g., replaced the heavy glass with some plastic-like material to save weight without compromising the picture? And are there any heavy components in the mechanism itself (Coils, Magnets?) that would have had alternatives?

I know it's just theorycrafting, but I do wonder what kind of CRT someone could've created if it wasn't for market economy forces.

The next big thing was supposed to be Field Emission Displays. Microscopic electron guns directly behind each phosphor. The big manufacturers experimented and tried getting it commercialized for decades, then pretty much gave up in the 2000s when LCDs got stupid cheap.

https://www.engineersgarage.com/field-emission-display/

There was also a brief reign of plasma TVs in-between, now almost a forgotten technology

A good 720p plasma is still a great display to this day.

I have the second to last generation Panasonic plasmas. 42" 1080p display. At first the picture was amazing but over time it degraded slightly with what looks like subtle noise affecting the entire display. Solid colors have a faint shimmer of noise in them. As if white noise was blended with everything.

I still use it as a bedroom TV. I can barely lift it myself and it claims to use 450watts of power. It's certainly a lot. It's notably warm near it and will heat my room if I don't open the door.

Still the picture quality is very good at a distance. Only oled or micro led displays look better.

This could be that you just noticed it? Panasonic plasma cells brightness is controlled by PWM off a 600 Hz carrier (it's even proudly advertised as "600 Hz!" on the TV box and stickers). While the number is quite big and stands out nicely against "240 Hz" advertised as refresh rate for the competing LCD TVs, it did not provide many different brightness levels per pixel (keep in mind that it's divided by 60 Hz or higher frame refresh) so those TVs were running temporal stochastic dithering to create more levels. If you looked closely at a new plasma TV screen it was very noisy with random pixels firing up at high frequency.