Yep - if you chose to develop something by paradigm alone we'd all be using PureScript: but there's so much more that's necessary to make something that needs to be around for 5+ years. Having FB dog-fooding and putting so much resources behind it is comforting and gives an acceptable trade-off of paradigm vs practical-ness.

Until Elm/Cycle/whatever's next have been around for along time and become established then to pick a framework to base a serious project on you're in the "two kinds of languages: the ones people complain about and the ones nobody uses" category.