The Roadster is probably all battery, no reason to think its not 2000 lbs of battery and 1000-1500 lbs of car. Is there anything to indicate lithium batteries

The Roadster is probably all battery, no reason to think its not 2000 lbs of battery and 1000-1500 lbs of car. Is there anything to indicate lithium batteries will somehow get 60-70% lighter in 2 years?