True. To me, each of those has a draw-back which, in my opinion, is greater than lack of 4k.
Specifically I despise the Roku UI and remote. To me, it is the worst designed user experience since MSN WebTV. ChromeCast is pretty nice, but I don't want to rely on a smartphone to control things, rather I want it to be a standalone thing that will work all on its own. I don't subscribe to Amazon Prime, so most of the FireTV features are useless to me.
Buying a TV with a built-in ecosystem, like Samsung's Tizen-based SmartHub and LG's WebOS 3.0, is a decent solution too, with obvious downsides.
Apple's solution just seems like the best mix of UI, simplicity, and apps.
I guess what i meant to say is over time the chicken egg problem will solve itself. with other options people will slowly adopt competing technologies. 4k will gain importance over the next 5 years and 4k content should be the norm.