>>Audio is optimized for theater sound systems.

My guess is that it's mostly this. I haven't noticed an issue with dialog (excepting movies like Trainspotters) in spite of having reduced hearing. The reason? A decent home theater with separate speakers and some attention to room acoustics. The dialog usually comes out of a different speaker than the effects of that moment - and our hearing systems (ears plus brains) are pretty good at sorting out directional info.

If you have a digital sound bar, *some* of those can do effectively the same as true surround but most cannot - and those able can only do it for limited viewing positions.

I'm a little baffled that people can spend $$$ on a big 4K screen and skimp on audio.

>>...only a few solutions to this problem. One, buy a better sound system for your home TV

Yeah, this, exactly this. It doesn't need to be an amazing system, but separate speakers makes a huuuge difference in intelligibility.