Well, if you really have to put in 10,000 hours to become expert at something, that’s just under 5 years worth of 40 hour weeks. Of course, if you just take the same photo over and over, a million times, you may not learn that much. Someone with aptitude who is shooting a variety of things may learn a lot more in less time.
Some people can get a lot from reading a manual but I am always amused when I get on a long haul flight and someone is on the plane reading their camera manual. On your way to an expensive vacation is not the time to figure out how your camera works. It would be even worse if they were on their way to a job. I like to get camera gear a couple of months before I expect to need it and try to wear it out while waiting for the event. Sometimes everything goes smoothly but as with the last lens I purchased, sometimes adjustment is required… Better to find out ahead of time so there is no panic while waiting for the repair shop. Then again, I am the proud owner of a Nikon FM-10 because I went to Hong Kong without a camera! When I saw the way their buildings were decorated for Christmas I knew leaving my gear at home was a mistake so I popped into a camera store. I ran a roll of film through it in Hong Kong Park and an hour later had proof it was working properly. For the rest of the trip, Kodak Express did a wonderful job of processing and printing for me. We could drop off film on our way to the hotel and pick up prints for family and friends in the morning. On more recent trips they have done that for us with digital files.
Photography has a whole spectrum of experiences. If you shoot some commercial work, you can spend weeks planning the shoot and take days to do the shoot. At the other end of the spectrum is weddings, news and sports; you either get the shot or you don’t. A lot of photography falls between the extremes and with digital you can chimp to see if you got what you want and re-shoot. Portraits and engagement photos fall into this area. Digital has definitely made some things easier, and other things more difficult.