What year is your TV? I have a C7 and a Samsung that's a year older with really good spotify apps. They even added an amazon music app at some point way after. But I have noticed some of the newer apps don't seem to make it.
As far as TVs getting abandoned, I think it comes down to testing and support more than anything. Then secondary, a sales incentive for a new TV. The C7 to CX jump isn't that huge.
I'd love a WebOS box. It's just so much better a TV OS and remote than anything Samsung, Roku, Fire TV have. I have all and I hate using anything other than WebOS.