Well, I suspect that everything in the universe is going to be around forever at the atomic level.
As far as recycling them - there are tons of places where they will be useful - EV batteries need to be able to discharge a lot of energy in a hurry and recharge in a hurry - a lot of the degradation that happens with these is not just capacity - but these attributes as well. But, even if you lose these qualities - you can still use them in other places.
I am willing to bet you will see tons of them reused as storage devices for renewable sources that you can not use easily now - like solar and wind generated energy - for example, see the Tesla Powerwall -
https://www.tesla.com/powerwall
Now think about putting these in places where you can put a lot of them to store energy that is created in unpredictable fashion - like wind farms, solar farms etc...
Other places where you will be able to use them - Nissan / Renault are using the really crappy first generation air-cooled batteries from the 1st generation Leaf in utility vehicles in their factories. I am sure there will be a lot of places where you can use these - just put a ton of these sub-par old batteries in the school buses - they do not need to go far nor do they need to go fast - so even the crappy batteries you would not want in personal vehicles will have lots of places where they will be used.