Should aspiring entrepreneurs quit their day job to pursue their goals?

For some people, sure they should. But for those who have financial commitments and don't want to overstress themselves it's important to note you can be an entrepreneur without quitting the day job.

I'd personally take baby-steps and mitigate the risk. Look to drop down to a 3-day week at the company. Consult alongside the startup. Work during your annual leave/evenings. Etc.

But I also appreciate that's not possible for everyone.

It depends. When your business starts to grow, you just don't have another choice.

But if it's small and doesn't bring you enough money yet, I suppose it's ok to have both.