No mate, there has to be other reason - Greg Chappell was 6'2", so was Dean Jones, Mark Waugh 6'1", his twin probably 6'0", Panta 5'11", at least 5'10", Hayden 6'3-4", Martin ~6', AB 5'11", Walters was probably 5'11"; I Chappel ~ 6', Gilly 6'1", Moody was 6'7", Hussey ~6', Lawry was parallel to Simpson & both looked at per with Ian, my memory tells Redpath was taller than Ian ............... 6' = 183cm ..... you +/- 2.54cm with every inch. I might be missing few figures but, surely every one was much, much taller than 170cm.
Taller players are indeed better front-foot player, but they can be great back-foot player as well. Add Lloyd, Barry Richards, G Pollock with the above list......
It must be somewhere else - may be changing Aussie wickets, may be coaching method, may be too many LO on flat belters, may be declining pace of domestic pacers, may be too much control on short staff in domestics/nets ....... but it can't be height.