re: Spinoff: anyone quit their high-paying job to start their own firm?

I did.
For me, it was what I had to do because I did not enjoy the "corporate" mold.
It took at least 3 yrs to stabilize after enduring hardships. From there, opportunities increased tremendously. 20 yrs into self employment this year!

And yes, all great things are worth the time, dedication, study, practice, failure, and lack of sleep. Worth.