Just putting this out there, many TVs and Monitors can't display above 60fps.
Most people dont have 4K tv's. But as time goes by more and more people are buying them. As time goes by more and more tv's and monitors will be capable of above 60fps.
I'm skeptical about the last point. High refresh rates are a much older thing than 4K, yet true high refresh rate TVs aren't really much of a thing, which is both due to, and reflected in, the fact that there is no high refresh rate content available for the living room. The only significant market for high refresh rate displays has for years been competitive PC gaming. So, unless something drastically changes in the coming years, high refresh rates will remain the niche market they are.
Contrast that to 4K, which only in 2012 cost you an arm and a leg, but now you can buy yourself a 4K TV for few hunderd bucks. Netflix offers 4K streams, some TV networks have plans to begin 4K broadcasting in the near future, 4K Blu-Rays of latest films are already available, console manufacturers are already using 4K as a selling point. 4K has already surpassed high refresh ratesin interest, and even though I don't have the data, I'd be willing to bet that 4K has also surpassed high refresh rates in market share.
High refresh rates aren't a thing in the living room like 4K is, and never will be unless something changes drastically. For that reason there isn't much of an incentive for developers to enable higher refresh rates, and it ultimately comes down to their graciousness.