I'm sure most of us realize that, and even have pointed it out multiple times, but it gets overlooked.
This is all about risk management. Wealthy owners, just like wealthy people, take typically more risks. The higher the risk, higher reward. The risk that owners take is spending cash to invest in players now which helps keep the cap number low in future years. They also have to make sure they sign the right people. If they have to trade one of these guys that they re-signed, (Stafford, Donald, Kupp) dead money goes through the roof.
Also, with the cap gradually getting higher, the earlier you invest (sign and re-sign players) the cheaper your overall investment is. It is no different than taking care of Kyler/Lamar at the beginning of the NFL year, instead of the typical August/Sept window. The longer you wait, the more expensive it is.