Like everything else in life. The answer is "It depends".

There is nothing stopping you from learning more with your current job. Regular working hours still leave you with free time on the weekends, and maybe an hour or two every day to read up on stuff you like.

Lots of people here, bootstrap a company along with their day jobs. If one's really motivated to learn new things, then status quo is always unsatisfactory.

I personally would advise, that you might try working on your own ideas rather than for someone else. You're bound to learn more.