You think Tesla will have cheaper batteries than literally everyone else forever? Incredibly hard for me to believe that at least one company won't be able to create a competing battery. Differentiating on hardware has never been a way to create a trillion dollar company. It requires lock in via incredibly brand loyalty and Tesla doesn't have a big enough customer base atm.

Not forever but long enough to become the leader. Apple continues to innovate despite plenty of opportunity for everyone else to catch up.