This in particular doesn't hurt it. What hurts is that UFC 224 was Nunes vs Pennington.
Cards used to have high buy rates because the UFC always put on great fights. The UFC name was a stamp of good fights and good names. 99% of fans only know who Brock and Conor are. When a card wasn't headlined by Brock or Conor, those 99% of fans bought cards because the UFC name meant that it would be headlined by someone like Stipe, Romero, or Cormier. Fans were ok with spending $65 knowing that they would get that product.
Now, the UFC name means that $65 cards might be headlined by Pennington.
So, that 99% doesn't buy the UFC name anymore. That means that Romero, Stipe, and Cormier will only sell slightly above what Pennington does instead of a bit below what Brock does. That 99% only buys when they see Brock or Conor now. They don't know who DC and Stipe are. They could be manlets or bums and casual fans are not going to research it for themselves (research is what "hardcores" do). They don't trust anymore that the UFC didn't load the main card with women, journeymen, and manlets. The UFC lost that trust by doing just that.
Holloway, just like Stipe and DC are, was mostly meaningless to this card's buy rate.