I think they're saying there is more value to be extracted from the current spend and, by implication, additional expenditure would just be good money after not so good.
When you estimate what some of our higher paid players are being paid compared to what they are currently delivering on the park, and are now saying they are incapable of delivering (a higher standard of possession based football), I find it hard to argue with that view.
P.S. I wonder to what extent Gareth's disparaging comments about supporters sheets back to what he has read on this site and, in particular, the "world owes me a football club" type posts i.e. just happily hand over your $s and leave running the team to those who know better.