Again, it's the easiest defensive position on the field.
I don't agree. It's LF. The reason older guys move to 1B is because they can't run anymore. But for guys who can still get around, LF is much easier than 1B. There's a lot to playing 1B -- receiving and making tight throws, grounders, line drives, groundballs, foul balls, double plays, bunts, pickoff plays, rundowns, etc., all in much closer space than a LF has.