It would help. But not every NFL team goes 8-8 either. It’s not that easy either to build a good team even with a cap.
There are still consistent sad sack badly run teams going on decades now. The Lions. The Cardinals with the exception of about what 4-5 years were they made a SB and had 1 good year with Carson Palmer. The Dolphins were so mediocre to bad for years. They still really are. The Bills went about 17 years with no playoffs. Even worse than what the Bengals went through. All this during the cap era.
And do I need to mention the Browns since they came back into the league in 1999?