I admire your optimism and I hope you’re correct. At least with the little “city commuters” it probably even makes sense. But lithium battery tech also continues to improve – so catching up with 2021 is great, but the goalposts keep moving.

There will be an absolute limit coming from physics and chemistry, and lithium is a smaller, lighter ion. In the theoretical limits, it will absolutely be the winner.

But from a practical perspective, if Na-ion becomes light enough and (more importantly) cheap enough, it will probably win the economic game in the longer term.

Plus we can make Na-ion batteries in-situ elsewhere in the solar system without having to first finding concentrations of lithium – so high tech space industry stuff will likely more towards Na-ion, which will fund some development.