Adopting something like elm might have its advantages, but also comes with practical disadvantages that, depending on your team and your project might be simply too big make the jump.
React got a lot of things right in my opinion. So much that to go from apple to fruit salad, you need roughly 200-300 additional LOCs, and you have a very robust Frontend system that, once you wrapped your head around React, has a very low knowledge barrier.
However, the good traits of React are not attributable to one concept like "FRP" but are simply "good concepts" that seem to influence other Frameworks to do "the same, a little different".
The adoption, the somewhat small API, the support from a large company, the possibility to integrate it easily in existing codebases that use other frameworks and react native has a much stronger pull than FRP in my opinion.