Half of the founders will say never quit. The other half will say you have to fail fast. Choose your gurus wisely.
Context is everything. Ultimately you have to use your own judgement about what makes sense because no one can see all ends. Generalized advice from someone without skin in the game is at best a weak datapoint for any significant life decision.
That said, let me give mine. Persistence over generally pays more dividends that constantly chasing quick wins. The modern information economy has cheapened success and skewed perceptions of how much effort and luck is behind outlier winners. The success I've had in startups was not quick, was not a straight line, and honestly probably didn't net me as much as if I had joined Google or Facebook early career, but the benefits in terms of broad skills and success that I can credibly claim on a personal level are actually more valuable to me than a larger number in my bank account.