I'm like can't they just steal another car from a dealer ship

right? even if time is warped weirdly depending on the area there, if most the buildings are stable enough to not have collapsed yet be overgrown by plants, the odds they can find a functional car stored inside of a dealership or garage isn't too impossible.
Major downside to them being in a dense city, most the garages are elevator style so I guess that might take longer too though