Some people do drive their
Some people do drive their cars for extended mileage. I took a Datsun pickup to 300k. But that is not "normal". Typical US car life is about 150k. With higher quality vehicles now being produced and people having less money I wouldn't be surprised to see that 150k raise over the next years, but this is a side issue. The topic was EV battery life.
We're seeing Prius batteries lasting for the life of the vehicle. Some hitting 300k. I think we can drop the worry about battery duration. Some will fail before 300k, but the same can be said for ICEs and transmission.
--
I don't think 500 mile range is important. Very few people drive long distances frequently. Try to identify anyone who has a 500 mile drive even once a week. Most people do that sort of driving once or twice a year.
Roughly 175 miles with 90%, ~20 minute charging will do the job. Drive 175, stop 20 min for a charge, drive 158, stop 20m, drive 158. You've driven 490 miles with only one more stop than you'd make driving an ICEV for fuel. And few would complain about the second stop if they can grab something to eat, pee, check their messages, etc.
Daily functionality is what counts most. If people can drive a comfortable, well-performing car for $1/gallon and not have to visit gas stations for fuel they will be a lot more willing to take an extra break or two on their infrequent long trips. The question for most will not be "How many miles can I drive without stopping", but "Can I get to wherever I want to go".
--
PHEVs may have a great future, at least a near term future. GM is releasing full sized PHEV pickups and SUV. If they can get the price down to a reasonable level those are going to be some very popular vehicles. Forty miles on cheap electricity.
The big question is how soon better batteries appear. If we call the Leaf a "solid 70 mile range EV" then we're roughly half way to fully functional EVs. We've got a lot of very smart people working on battery tech. There are immense fortunes to be made. The technology could move very fast.