Yeah, because disabling it in SOFTWARE makes it impossible for the tv to activate it when your not looking right?
If you want to be totally safe, you need to cripple the hardware itself!
And how hard is that? In my home, the wifi is encrypted so if the TV connects via wifi, I simply don't give it the key. If it connects via ethernet, I disconnect the ethernet cable. It's not too hard to prevent the TV from phoning home.
As for the original question, at this time it doesn't seem like there are too many options for this. I bought a "smart" tv several years ago, I thought it would be helpful since I wanted to be able to stream Netflix without getting a third-party box. The interface is terrible, it's very slow and unresponsive. There haven't been any updates to the "NetTV" portion of the software, so pretty much the only thing worthwhile is Netflix - most of the other services it supports either are useless or don't even exist anymore. If the company cared about providing updates and staying current with services it might be worth it but there is no motivation for the company to provide software updates since they would prefer I just buy a new TV if I want access to current services. With things like Chromecast and FireTV, it makes a lot more sense to get a dumb TV and add the smart features you want via a cheap dongle rather than paying hundreds of dollars for the TV manufacturer to add the same hardware with a crappier interface to the TV.