As a big offset for those potential improvements, there's the unavoidable fact that as any machinery ages, the wear & tear brings out failures.  Rust, friction, electrical short circuits and all sorts of unexpected lapses and expensive failures. 

The public might expect that the high cost battery packages, from $12K to $25K would have premium safeguards built in.  But when we learn there's been chemicals producing high temp thermal runaways, its quite disappointing.  Seems evident when there's spontaneous combustion and the re-igniting,  that safety hasn't been addressed well enough yet.   

An example is when FORD's band new f-150 trucks spontaneously caught fire. Those vehicles had not been driven at all,  Defective expensive batteries from the get go.  And now, after the fact, FORD is modifying that battery design. 

Fire safety officials have pointed out how the result of EV fires have mostly resulted in total losses of the vehicles.  Entire costly investment is gone up in smoke. Seems to be "worse case" results.  It's one reason why EV insurance is very costly.  

EV's are Crushingly Costly for many retirees to buy, or to pay the high $$$ insurance on.