I don't disagree, but I've gone the opposite way.
Just last week I replaced a 46" Samsung 1080p set from 9 years ago with a brand-new top-of-the-line Sony 4k set that has all this fancy AndroidTV stuff I neither knew I wanted nor really understood.
Thing is, it's the ONLY way I can get 4k content.
I have an HTPC, WDTV, AppleTV, FireStick, PS3, and TiVo all plugged into my receiver (which was a very high end unit just 1 year ago). However, while the receiver supports 4k, it does NOT support HDCP 2.2 which either is required for 4k content, or WILL be once they start using HDCP 2.2. (I'm not quite clear on this point.. I don't know if today's UHD BluRay discs use HDCP 2.2).
And I'd argue that the SmartTV stuff is not really a reason many people buy a TV; regardless, having it does not remove your ability to use external devices in the future. If Sony drops my AndroidTV apps in 4 years, it probably won't much matter because the devices of the future will do far more for $35 than the software on the TV.
It's a frustrating situation, but, IMO, the Smart TV stuff only adds value (unless you're talking about the microphone in my remote and the possibility of said devices being used to backdoor my network, of course).
I forgot to add, new things pop up all the time that you don't know you want until they arrive. I noticed Google Photos being advertised on TV. I gave it a go on my iPhone and notice a Google Cast button. I don't have any of Google's streaming devices yet, nor do I have an HDMI port free on my receiver to support another device. Well, I hit the button, and what do you know, it automagically knew all about my TV and displayed my pictures at the touch of a button. Sometimes having fancy new stuff is cool, and you get added features you never expected. I sure wouldn't buy a Google streaming device just for this one novelty, but I'm not going to complain about having it.