There are already solid state batteries on the market. We aren't actually talking about 'solid state' at all, that just a accidental marketing name. The things

There are already solid state batteries on the market. We aren't actually talking about 'solid state' at all, that just a accidental marketing name. The things that is the actual 'hotness' is lithum metal anodes. The reason why people use the term 'solid state' is because it was thought 'lithium metal' anodes would only be possible with solid state. So companies taking a long time to develop lithium metal anodes doesn't mean other battery types that use solid state will take as long.