Well the ones with li-ion batteries ought to last at least 2000 cycles, or about 6 years with a cycle each day, but there are lots of mid tier models being made with lifepo4s now, and those last like 6000 cycles, so there is far more breathing room. They're also cheaper so you may be able to more easily break even.
That just means people will buy daily drivers with small batteries and charge them nightly. 15 years out of a cheap compact car with near zero operating costs sounds like a good deal, still does not make sense to waste a cycle for $1 = 20kWh fed into the grid.
