I could be wrong but I don't think the majority of Scottish clubs have got enough players for an old-school reserve team, so it just ends up being a youth team anyway. With as many as 16 "senior" players involved in every league game, there aren't many left over to play in the reserves.
As for Fletcher, 16 does seem a bit young to be playing any kind of regular first team football so, as Panda says, he's as well staying with us, training with the first team when appropriate and making the odd appearance here or there.