Bud -- I'd say vacation -- not retired. Rob -- he just retired from teaching.
My guess is the last thing he'd want to do after a lifetime of working and teaching is take a FULL TIME gig in radio. There's a difference between being the fill-in guy and the full-time guy...especially at that stage in the game. Rob can have a blast filling in for Bud, Sue, Corbett, whomever. It's a great gig for a week. You come in, have a little fun behind the mic, and earn some beer bucks.
But to retire from one job and then have to go to the grind every day, sign a "no compete," not be allowed to take vacations during the spring or fall books, have to show up at free events (parades and what not), etc. Great when you're 25, sucks when you're 60.