You're grouping clubs into two broad groups and looking at the results of grand finals as your only data point and assuming they're the product of bias.
If you look at it more holistically, non Vic clubs have been very represented up the top of the ladder and haven't been overrepresented down the bottom of the ladder. And it's been Vic clubs most inclined to find themselves stuck in the bottom half for lengthy periods.
We've had 3 great teams from Vic - Hawthorn, Geelong and Richmond win a heap of flags skewing the grand final results towards Vic. Prior to that we had a great team from QLD doing the same, with a NSW, WA, and SA team regularly up there getting close throughout the whole time.
15 of the last 17 Grand Final winners have been Victorian.