Here's what happens when your Tesla Roadster (or any EV) reaches the end of battery life

I really don't think battery power is the long term answer. Not really up on new(er) technology, but what about the hydrogen fuel cell or something similar?
Battery power is much more convenient to use so I guess that in the long run hydrogen supporters will give in. In an interview Elon Musk once discussed the disadvantages of the hydrogen technology and said that it had zero chances against electric power.