Originally Posted by sdsearch

And Thrifty and Dollar are the same company.

So perhaps it's because you're comparing between when there were "effectively" twice as many rental companies as there are today? Ie, although the rental companies may have merged a few years ago, it might be only more recently that they've figured out how to make one inventory work across all of the now co-owned companies (at least at airports where the co-owned companies are close to each other). So before that efficiency, if Avis ran out of cars and Budget had plenty of cars, Avis couldn't use those Budget cars. Now, presumably, at more airports they can, so they only look it as one Avis/Budget inventory instead of a separate Avis inventory and a separate Budget inventory. And it may be a lot easier for them to more tightly match the number of cars reserved to the number of cards on the lots if it's treated as one combined inventory rather than two separate inventories.

(I'm just using Avis/Budget as an example. I didn't even factor in that they also now own Payless. The same example could be constructed with any other recently merged groups of car rental companies.)

Here's an idea: Maybe you should like into "independent" / "minor" rental companies, especially if you're not tied to airport rentals. For example, here in SoCal there's also Rent-a-Wreck, but they're not found in the typical airport-based rental car searches. So are such "independent" / "minor" rental companies equally effected or not?