I can't remember the last time I really needed to rent a car. Maybe for the random site-seeing roadtrip. But vacationers aren't rental company's bread and butter: it's business travelers. And business travelers are seeing much more convenience from rideshare than from rentals. The hassle of renting a car, parking, tolls, gas, dealing with insurance and liability, and just the shenanigans of rental car companies is not worth the hassle.
It took a solid decade before the impact of video on demand was felt on Blockbuster, but it was inevitable.
Just how COVID is bringing the water out of shore on the low tide, all it is doing is exposing already weak companies. Those that fail can't simply blame COVID, altho it's certainly a contributor. For some, the writing was already on the wall.
In 10 years we'll be writing the post-mortem on the rental car industry.