When was the last time a team got pumped in a GF and came back the following year to win it all? If memory serves very few even manage to make the GF again or even contend.
North came back from a 35 point loss to win the following year 1998-1999. Not really a pumping given it was only 35 and it was 30 scoring shots a piece in 98.
Geelong lost by 80 in 1994 and came back to lose in 1995 by 61.
West Coast lost 1991 by 53 and won 1992.
1985 Hawthorn lost by 78 and won the following year.
So it can happen, but if we take 50+ to be a pumping, in the last 50 years the pumpee has made the following grand final six times (12%) and won four times (8%).
There has been 14 pumpers, with pumpers making nine following grand finals (64%) but only won three. So history says a pumper has been relatively unlikely to win the following grand final. In fact, a pumpee has won four, and a pumper three, so maybe the The Western are onto something.
Anyway, most of the big turnarounds have been from 20+ years ago, in recent times the pumper has been relatively successful and the pumpee not.