... that it "falls victim to a cost of living crisis", then maybe something was severely wrong with the business model to begin with. Sharing cars should be substantially cheaper than "owning one's own" - if it is not, then why would anyone want to "share" it with strangers?
OK, not being an Angry Individualist American On The Internet(tm) I'm not pathologically allergic to "strangers". With that aside, it is a lot cheaper. The alternative to zipcar is generally speaking not using a car at all. The alternative is therefore largely speaking free. I have had good use out of a cargo bike hire, which is also much much cheaper.
Before you argue about the necessity of a car, just remember that fully one third of Americans do not have a license, and in the UK that number is one half. In the area of London, where I am, over 65% of households don't have regular access to a car.