With Getaround and Car2Go out there, ZipCar needs to make some big changes to its model in order to stay relevant. But I generally agree with Pearlstein: Avis does not have a track record of innovation that would suggest it can make those changes.
Zipcar has already fallen behind the others as you mention. I don't know how Avis expects to fix it, but if Pearlstein is right, this is more like the auto/oil companies buying up streetcar lines ~100 years ago. Just to pave them over and remove that source of competition. Though it's likely too late for that.
"What you got Avis? Come at me bro!" - Carsharing