The profit they get from a tv is a single sale. The way they want to make money nowadays is as passive income, that's why they're pushing all the subscription services everywhere. It's a lot more money for them.

Think of it like this: a $500 tv can earn them $50 profit, but $5/quarter for the same tv means they get double that profit in 2 and a half years. And they'll probably make triple or quadruple that, so they get 4 times as much money for the same tv sale.