That's true, but a projector, once setup, is no different than a TV connected to a surround receiver. It should always be used with a good remote control, but you still are just powering it on and off, and that's all you should need to do once it's setup.
I have a motorized screen, a projector on a lift, along with all of my sources... But, to come in and watch cable I pick up the remote and press the button that says 'CABLE' and that's all I need to do.
A TV will typically have terrible sound on it, so you still would want the surround system and the rest.
Still, it's nice to just set it on a table and walk away. But, if you own a home, and you are putting in the effort to make a space a really nice 'home theater' area, then the extra time spent to really set up what is needed to make a really nice home theater is well worth it. I mean, while 70" sounds big, it's about half the size of what a theater would deliver, and may cost the same amount of money overall.