>I really have no idea how long the average consumer holds onto a TV, but if we guess 3-5 years
3-5 years is smartphone life. New TVs should easily last 10 years. My $600 1080p TV from 2016 is still in the living room. A subsequent $600 4K TV bought in 2020 is also fine. I don’t see what could prompt me to replace them until they break. The quality difference is negligible, especially with the garbage bitrate most streaming services provide.