I spent two years just getting really good at React before branching out. That deep knowledge let me fix problems nobody else could, which built my reputation. Now I'm learning the broader ecosystem because teams do want you to connect more pieces.
But how often do you actually run into problems that only a React deep dive can fix? Most bugs I see come from not knowing how parts fit together. Spending years on one tool might make you good at it, but you could be slow to adapt when things change. Teams value people who can pick up new stuff without a two year boot camp. Your way worked, but it sounds like putting all your eggs in one basket. I'd worry about being left behind if React falls out of style.