You misinterpreted what your stats mean. In fact they make my point. The market for amazon/google/whatever HDMI sticks is evidence that consumers are looking for a smart experience. But they exist to support two other market features: a) TVs last a long time. b) media updates don't. Virtually the entire market for those sticks exists to support existing dumb TVs, or smart TVs that were abandoned (e.g. we went out and bought a Google Chromecast when our 10 year old smart TV stopped supporting Netflix, we then proceeded to sell that Chromecast when we bought a new TV because the new TV once again supported Netflix.
There's no evidence that the world is moving away from simplification / unification. The sales figures and market size of smart all-in-one devices and continued sales of new smart TVs is evidence of this. And the app experience while shitty is not at all related to this trend: in fact it once again supports my point that consumers are chasing smart integrated experiences and will go so far as to use shitty apps with horrendous UX to get it.
Go ask any of your friends with a new TV if you can borrow their Roku. I'll bet you a Marsbar they will say one of two things: 1) Sure, we're not using it, 2) Sorry we threw it away.