Batteries are quite good already. You can wait for the next big thing, or get something that works and scales right now.

Battery production is now measured in multiple twh of capacity per year. That goes into vehicles of all types with any number and size of wheels, grid storage solutions, and domestic storage. People use them all over the world now. Including some developing economies.

There are many quality attributes you can look at with batteries: cost per kwh, weight per kwh, volume per kwh, charge/discharge rates, longevity in charge cycles, operating temperatures, robustness, chance of flammability (near zero with some cell types), etc. Better is a meaningless qualification unless you express it in those.

And what is best and what is optimal are two things. There's a reason LFP is dominating rather than NMC. It's good enough and a lot cheaper even though it has slightly less energy. For the same reason sodium ion is being put into some cars. It doesn't have the energy density. But it's cheap, operates in arctic and desert temperatures, and they last pretty long.

When it comes to new battery chemistries, it takes time to go from a lab breakthrough to mass production. Sodium ion is now being mass produced. A few years ago there was only low volume production. And before that, the technology was stuck in various stages of the R&D pipeline at various companies. From a lab prototype in a university to an actual proof of concept might take several years. And from there to production many years longer.

With solid state, there are about at least half a dozen technology companies that are moving from test samples to low volume production in the next years. Mostly the technology is proven and validated at this point. But it might still take until at least the end of the decade before we see any mass production. Building big factories costs billions and is super risky. Companies don't do that unless they are certain something will work.

Solid state will have to compete on quality and price. High density solid state in cheap cars is not likely to be a thing for cost reasons. But they might be popular with drone and sports car manufacturers. The press is unfortunately a bit sensationalist on this front and it creates unrealistic expectations.