Sure, understood, but because cost wasn't mentioned in the OP doesn't mean the budget isn't a consideration. So, I just wanted to make mention of it for consideration sake as well.
What's the time frame for obsolescence and what is really considered obsolete? Pete posted an article a couple of weeks ago stating that the last VCR's would be manufactured at the end of July. I haven't used a VHS in years and considered them obsolete a long time ago, yet someone is going to buy one of those VCRs and use it for years into the future. So when is the VHS/VCR obsolete? Technically, they still work...
Similarly, an HDMI cable rated for 1080p or 2160p will be viable for a while into the future. Media connection protocols don't change all that often. Coaxial cable is still being pulled into new construction homes as the primary CATV backbone. Will it become outdated eventually, sure. What won't? I see many LV contractors installing HDMI cables into homes right now as well - much more often than them pulling CatX and using baluns. Understand, that doesn't mean either way is right or wrong - they both work.
Is a CatX solution more flexible? Yes. Does it have more failure points? Yes. All tradeoffs that I consider when making decisions such as these.
If it's me, I'm pulling a single HDMI cable and calling it a day. If it no longer fits my needs and needs to be replaced in 10 years, so be it. If another protocol comes along, you may also begin to see similar converters than then use the HDMI cable to convert to the new connection protocol - whatever it may be.
The closest thing I've seen to replacing HDMI is HDBaseT and I haven't see much widespread acceptance to it. Are there products made that use it? Yes, but I don't think I've seen one on the back of a TV yet...