There isn't a solution to devices becoming obsolete because manufacturers would sell less of a new product if the old one worked fine in perpetuity. Not only this but old iPhones, for example, run worse with new iOS versions because new versions are coded for new hardware. Hence the need to upgrade periodically. How many of us have a 486 that will run Dragon Age?
http://www.samsung.com/us/2013-smart-evolution/
It being Samsung, the hardware upgrade was apparently offered after a single year and completely redid the UI, but there's no reason the same principle can't be executed competently.
So from what I understand about the Evolution Kit, it attaches to TVs 2012 and later and provides them with a boost to put them almost on par with 2013/2014+ TVs? Doesn't this cannibalize sales of new Smart TVs?
Funny enough, I had a single remote setup for one brief shining moment in 2008 with the second generation Apple TV; the AppleTV would switch on and off my HDMI TV using some precursor to CEC - the same sleep/wake function that modern PC monitors use - and could also control the volume using the up/down buttons on the remote by modulating the sound going over the HDMI connection. Unfortunately, Apple ripped this audio control functionality out with a software update a few months after the product was released and I was forced to break out the second remote again and eventually replaced the AppleTV. But the point is it is possible to have only one remote with an HDMI connected set top box, but that feature isn't a priority in the world of cable boxes and audio receivers.
Anyway, my experience with smart TVs is that they're a waste of money and incredibly frustrating compared to set top boxes like Roku/Chromecast/FireTV/AppleTV. On top of that, my experience with TV remotes is that I don't want manufacturers like LG, Samsung or Sony making my primary remote control. They invariably feel cheap, slow and clunky whereas Amazon/Apple and even Roku do a very good job.
With TVs you're not usually lugging the devices around, but the TV has to be turned on and have volume (and sometimes other settings) managed with a separate remote. Since they typically have multiple HDMI ports, while the set-top boxes you mention don't have HDMI passthrough, you're encouraged to multiplex devices from the TV too, which requires manually selecting between numbered inputs with only a dumb OSD to help coordinate things. (If you have external speakers you might use a receiver to multiplex instead, but now you have a third remote and another dumb UI, not to mention potential latency issues for gaming.) In practice, the result is that among regular users, nobody can use someone else's TV without first being coached on their particular idiosyncratic combination of remotes, let alone try to play their own content by plugging a device in or wireless streaming or something shocking like that. Supposedly HDMI CEC helps with this somewhat by letting the device control the TV; I haven't used a setup with it, but there's only so much a standard for connecting disparate devices can do.
I want one remote - with the option to use my phone or voice control if I lose the remote - and a single, good UI that controls everything. That's only going to happen with a smart TV, but maybe the right device has yet to be made.
(One potential solution to obsoletion is for a manufacturer to make the brains of the TV a separate detachable part that fits into the design, like a laptop battery. Another would be to standardize on one HDMI port per TV, with CEC support and no UI when something is plugged in, so that you're basically required to plug in a box that then takes over the experience. Yeah, like that's going to happen.)