How long did this take? About five years.
He bitches now and then that he's the unpaid master class of the Hollywood TV industry. Not everyone (me, for instance) who's done time at Spümcø is working in the animation industry. But everyone who spent much time doing John's directed practice can draw rings around most people with their eyes closed.
The hard part, IMHO, was putting in the time to practice and keep practicing. Even on a shitty day. This guy seems to have that down; he's been able to structure his life so that he doesn't have much to distract him from golf. If he keeps at it and doesn't get run over by a truck, I'm pretty sure he will either become a pro or burn out.