i haven't read up on fuchsia/magenta too much yet, but my impression is that it's going to be a much larger shift in general.
If Google can take some less drastic strides to fix this problem before a huge change like fuchsia, theres probably a better chance for an easy(er) transition.
this is why I should stop commenting I stuff I haven't gotten super familiar with. I didn't know Dart was the choice for user space. I suppose they could theoretically include an compatibility layer for java/kotlin userspace apps, but that seems like a lot of baggage depending on what the real goal is.