The most likely change is the switch to plug-in hybrid electric vehicles (PHEV's) using essentially today's hybrid drivetrains with a much more powerful battery pack, probably using the ultracapacitor technology I mentioned. This would allow all-electric operation up to 80 km (50 miles) and standard hybrid operation after that. For example, I've read that the next-generation Toyota Prius and the new Honda Insight are designed so it the manufacturer could "drop in" a full PHEV drivetrain in a few years.
the japanese have zero reliabilty for backwards compatability.