Why can't a TV already have a good level of performance built in? A lot of times they do but every tech product is updated at least every year, so as to keep up the demand for the latest & greatest features.
If a TV, computer or smartphone is built well enough, it should be good for several years.
Unfortunately, planned_obsolescence is a clever way to get people to keep buying the same products more than they might otherwise, have to.
http://www.bbc.com/future/story/20160612-heres-the-truth-about-the-planned-obsolescence-of-tech
While it helps to increase corporate profits, it causes people to spend more than they need to.
https://gizmodo.com/another-nail-in-the-coffin-of-the-most-obnoxious-thing-1837668107
In whats supposedly a growing environmentally aware world, it would make more sense for products to last as long as possible.
https://www.consumersinternational.org/news-resources/blog/posts/built-to-fail-is-planned-obsolescence-really-happening
People will always want to get a new phone, computer, TV, or car, but not necessarily every year.