That said, it may also be a quality indicator: maybe RN users just have fewer problems. Maybe RN community members are better at documenting problems and their solutions outside of StackOverflow?
Flutter is where RN was three/four years ago, it's far too early to even think about calling it the king of cross platform.
- Learning a framework is still usage of the framework and so even beginner questions lag "usage" statistics
- Learning a framework is prior to "[Production] usage" of the framework and so beginner questions lead "[Production] usage" statistics and job descriptions
I think I lean a lot more towards the first take, especially in our industry: in general we aren't paid to learn new technology stacks, our companies don't budget for such training costs, and generally don't like it done on company time. Sure we make a big thing about "we are an industry for passion" and often force software developers to moonlight and learn things on their own time/dime "as a hobby", but I wouldn't like to think there are enough moonlighters and "hobbyists" to make something "popular" on Stack Overflow with just beginner questions.
When my team struggles with a new library or stack, we go to the maintainers' Discord. Most of them seem to really want people to engage there.