100% this.A ruck is one player. Do we say midfielders are overrated because their team loses?
Sydney had 4 on the AA squad and Brisbane only had 2. Clearly, its better to have less AA if you want to win a GF.
I get the argument for not paying a ton of $$ for a ruck, but you can't pick one position and one player and make general conclusions based on one game. Confirmation bias as its finest.