I don’t disagree that ebikes would benefit from a bump in battery tech, but that is unlikely for 3-5 years - billions are going into battery tech for decarbonising our economies, but when they come capacity will be limited initially and any breakthroughs will go to cars and home energy storage first. However as @R120 points out current battery tech still gets the job done providing you do your research on how to charge, store and use your pack. Just don’t rely on the manufacturers guidance; most of the ebike manuals I’ve looked at are woefully inadequate.
As is the long term battery tech, inadequate, charging extortionate amounts for second batteries, in my opinion, seems the tech is one that can't be replicated at a competitive price point, and in the long term, how will the batteries be recycled, If at all.