What usually ends up happening (at least since the last time I bought a TV) is that I can't find anything simpler for the same price since a big part of the (relatively) lower cost of modern high-def televisions comes from volume in manufacturing and sales. Since most come with some token "smart" capabilities, I end up buying something regardless of (or despite) the addons.
I just use a basic home-theater-in-a-box receiver for 5.1 sound and because it has a built-in Bluray player (which I have yet to use) and like 3 or 4 HDMI inputs. So I run the cable box into one input, Chromecast into another, game console or HTPC into another, etc. and then output video from that into the TV.
So in the end, I only use my TV as a display even though it has other features built in. Having all sources go into the receiver means I can just switch inputs and audio follows video. If I want to watch Youtube or Netflix or listen to streaming music or watch something on my NAS via Plex, I use the Chromecast. If want cable TV for some weird reason, I switch to the cable box, etc.
But yeah, a large format display should last me longer than the life cycle of the "smart" capabilities or streaming services. When I bought this TV, there were several streaming sites that didn't exist yet or I didn't use. I want to be able to add or remove hardware as I need it and I want to use services that are currently valuable to me (and not have to skim past all of the integrated ones I never use or don't exist anymore).
Right now the two options I see are to use a low-powered HTPC that is still more functional than anything in a smart TV and can be upgraded, or something small and cheap like a Chromecast or extender that lets me tap into sources on my network or on the WAN.