With the way the technology is advancing these days, what cost $5000 3-5 years ago you can get for $500 now. It's been like that for a while and will continue to be that way. The consumption machine must not be stopped! New gimmicks every 6 months so they can sucker people into buying a new TV every year or 2.
Personally I've never spent more than $500 on a TV and that was a Panasonic 27" CRT. My current screen is a Toshiba 1080p 43" that I paid $298 for a couple years ago and it suits me just fine.
8k is already here. Funny thing is, $3500 isn't even close to what would be considered high end these days. Best Buy is selling $20,000 TV's and people that want to put together a nice home theatre are not shopping at Best Buy, they're going to specialty shops.
But to put it into perspective, VHS players used to cost $1500+ back in the day which is $4500+ today. VHS tapes were $100+. A 19" TV was $750 in 1980, ~$2300 today. If you insist on having the newest technology it has always been expensive. It's just way harder to keep up and have it all nowadays with the rate that new tech is coming out.