>"The biggest problem is that sound on most TVs sucks. "
No. This is about the source material (and sometimes, but more rarely, the content delivery companies mucking around with transcoding).
Sound on all TVs has *ALWAYS* sucked, at least compared to actual home-theater setups. That is why who really care about audio (like me) have a "real" audio system, with 6+ quality speakers properly placed in the room and using a powerful, expensive Dolby amplifier and with the system properly calibrated by putting a microphone in the sweet spot and performing a self-test/adjustment.
The problem with dialog-drowning is real. It is in the content. It is intentional. It is not about the end-user's audio equipment. Rarely used to be an issue and has gotten worse and worse.
>"silly to have an 80" 8K screen with crappy speakers mashed against the wall it's mounted to."
Yes, it is. And even a "sound bar" isn't going to give a great experience. Not compared to "large", quality speakers set around the room and tuned to the room. But when the content is whacked, nothing works properly. And then you are faced with having to muck around with stuff, like boosting the center channel, or using "enhancers"/"filters", which throw everything else off.