I might be an optimist, but I don't see how aligning their thresholds with other programs would negatively affect the quality of the higher tier.

I myself would gladly return to Avis if I was afforded better recognition than First/Preferred Plus (obtained over a period of two months last year), which means Avis would receive more revenue. As it is now, I made all of this year's rentals with National, because their Executive Elite tier allowed me to have some very nice cars/SUVs (Cadillac, Mustang Convertible/GT, etc.) at the intermediate rate, even though National has less locations from which to rent, thus a smaller number of cars in the regional fleet.