The two games are VERY different.

A football is, as stated a very "stop-go" game. Rugby is a go game whith short breaks when the ball goes out of play.

A Football had off the ball blocking/tackels and so this becomes the dominiant part of the game and so people who fit that profie excel and so form the basis for the teams; you also have vast "teams" for A-footy where as the whole rugby squad will be 22 to play and maybe 30ish to pick from.

THe only real skills that instantly trransfer is the kickers and there have been many rumours of some of the top trugby kickers being offered large amounts to join the special teams of the big clubs in the US.

they are two games that look similar in the fact the ball is of similar shpae, but they are very ver different.