When you plan ahead, it's manageable. Sometimes, a car for renting is not available long term because people plan for the same time (e.g. holidays) and the provider doesn't have big enough car fleet to cover these peaks.

When you have an unexpected trip though, e.g. suddenly needing to go to Ikea, a spur-of-the-moment trip, etc., that's when this all falls apart. In my town, this was then 40:60, favoring no cars being available.

In the end, I just bought a car. 5 days out of the week, it sits on the street and depreciates in value. We take it on trips for the weekends, though, and have been absolutely loving it.

[0] central Europe, don't really need a car for daily life, but it's nice to have sometimes

I see lots of short rentals that just idle on the street for days sometimes. Here the provider pays of course (and I assume it’s not in their interest).