Most riders learn, soon after getting into commuting. At my workplace, I keep a floor pump and some odds and ends in my office / lab area, and folks are welcome to come and pump up their tires, fix a flat (with or without help), or get general advice and criticism from the several cyclists who are usually around. A couple of them have showed up with flat tires or minor mechanicals and no idea what to do. After a bit of coaching and reassurance, they're usually eager to do it themselves next time.
Myself, I'm 100% self sufficient for all bike related work, but it's a hobby of mine. I do tell people that getting up to speed on basic maintenance will vastly improve the utility and enjoyment of cycling.