Originally Posted by Auto Enthusiast

It's probably viewed the same as one-ways. Sixt won't buy thousands of new cars in CA while thousands sit under-used elsewhere. And that car may eventually wind up in still another region eventually.

The key difference is that, for some reason, Sixt seems to prefer to pay to reallocate cars itself, rather than lowering one-way rates, to incentivize customers to do it. There are some cases where Sixt one-ways are competitive, especially when they open a new station, but rarely.