It is. One of the reasons I posted this interview is that on top of doing $80k in monthly revenue, the founders are big Tim Ferriss fans and only spend an average of five hours per week on this project - one of the founders still works a full time job.
Doesn't matter if I like my job or not, if I am making 80k/month from my side business, I am definitely going to quit my day job and concentrate on my full business.