I think it isn't super uncommon. Software engineering is my second career, and unlikely to be my last. Probably 30% of my co-workers had a non tech career before getting where they are.

In my career transition I learned and grew a lot, and it helped give me a different perspective on some problems.

I do wonder if people changed their careers every 10-15 years if they would be happier. You would get to work on a whole different set of problems, you would get to learn new skills, and eventually demonstrate your mastery over those new skills.