Because it's only profits that must grow every year. And if you can't increase prices, or market share, or the market size, then you must cut costs. And if the only way to cut costs is to destroy the product, then that's what must happen.
As for tvs, with all the trouble I would have to go through to figure out if and where I could still buy a tv that is 100% guaranteed to be dumb, I'm pretty sure I'll never buy a tv again in my lifetime (which, taken the average lifespan in my country, could likely be some 30 more years).