Let me remind you guys again, 40 years there was only one form of cricket and was played in hardly 3/4 countries and against similar opponents. The kind of pitches and and weather they faced did not varied alot. In contrary, now the players needs to change their style, techniques and the approach of games every day against every team and against different format of games. A player is expected to change overnight from test match mode to 20/20 mode.