Sometimes a setup like that is the best setup possible, no ambitious team trying to make their mark by replacing something that doesn't require replacing or that they can't replace well enough. I doubt that JavaFX would have more impact if they put a team of dozens on it (or, shudder, hundreds) but they would surely make life harder for those who still build on FX. A larger team might have already declared javaFX dead entirely, urging everyone to port to some exciting new javaFY and losing many of the remaining users in the process, without attracting any new ones. Arguably Swing to FX was already a bit like that.