Indeed, the Croat has explained how new signings make a bigger impact for the likes of West Ham and West Brom - while Manchester City and Chelsea can't make as much of an impact in the transfer market as they already operate close to their peak.
Bilic told reporters: "Say Man City buy Karim Benzema. They have Sergio Aguero already, so there is no big gap for them to improve. There is no big space to get much better. Chelsea can sell Diego Costa and buy Robert Lewandowski, yes, but they are only different; not better.
"But clubs like us, Crystal Palace, West Brom, Leicester: we can still improve with the money. Two years ago West Brom maybe could afford Salomon Rondon, but they would have had to sell Saido Berahino to get him. Now they can keep Berahino, so next year, with more investment, you can keep those players. Crystal Palace can keep Yohan Cabaye and bring another one."
It's a sophisticated theory...
And it even helps explain wider issues in football. Why have Real Madrid been so poor (relatively) in La Liga over the last few years? They've had some of the world's best players but, whenever Florentino Perez has sanctioned big-money spending, it often hasn't improved their team. Instead, it's simply brought in one good player at the expense of an equally good player.
West Ham and West Brom are certainly seeing a level of progress each year, especially in the transfer market.
Next season will no doubt bring major challenges for both the Hammers and the Baggies - and sustaining success is the biggest challenge of all. Even Manchester City and Chelsea have struggled with that.
But the future definitely looks bright for both clubs.