What do think battery cost will be in 10 years. Would you be surprised that batteries in lab today demonstrate 100 year life? About the same energy density. Other lab research has demonstrated 4X improvement in energy density. So not a certainty but development tools are more powerful today increasing the chance of improvement. https://bob-n-martha-roth.medium.com/to-elon-from-millions-of-my-engineering-colleagues-you-are-welcome-4950e2b85554