A significant increase in the lifetime (number of discharge cycles is compelling though). Plus I'm sure if the technology is commercialised, those with vested interests will be keen to lobby that solid-state batteries are required in electric vehicles due to the claimed safety benefits.

Certainly legislation and regulation will be big market shapers. I personally think we should jump on every improvement, because it benefits society. But the cost is currently born by the factory owners, and they selfishly want to depreciate everything out before retooling.

I don't think it's as grim as you are making it out to be. Especially for companies like Tesla and apple, the use of the product is directly tied to the battery. I just think it is a difficult problem.

My niece is in this space (battery research/startups). They keep failing, even with 20% improvements in whatever, because nobody will retool. So yes, that's about how grim it is.