Age is the biggest thing with batteries.
When have you ever seen any type of battery last 10-15 years or more? In anything. I'm sure they will be some kind of built in expiry date anyway, otherwise it's bad for business if they last forever.
Long term, EVs just aren't the answer unless there is a major breakthrough soon to make them smaller and much lighter. Batteries in their current form are not the solution for transport.
Usual Masher levels of "thoughts"
I've got an MP3 player for example from 2006 that still holds charge really well. As its not used that much (mainly for travelling) its probably been charged 100 times and I don't think its far off original performance. It certainly holds enough charge to travel for 24 hours and have loads left.
Chemical and mechanical things wear out with usage, Im not sure your really giving us breaking news in this regard!
Why aren't EVs the answer. They offer real world usage now thats good enough for the vast majority, as the faster charging batteries become standard the recharge times aren't really high at all. The infrastructure is improving, quickly.
Smaller, why? The vast majority are buying bigger vehicles even ignoring EV impact. Is this another one of your "real car fans" comments, where you think everyone agrees with your views that we should/could all drive around in Elises?
Lighter why? For the vast majority they don't care how much it weighs within reason. I am sure as ever things will evolve. Faster charging and a really good infrastructure may well see smaller packs at some point in the future, but right now there isn't actually a problem so I am not sure why with progress we NEED to get lighter.
Most items that artificially kill batteries are relatively low value. I expect at some point someone will put forwards legislation to outlaw artificial expiry. Having a chip "kill" something thats in effect perfectly fine is beyond dumb.
Even with that said the cells themselves hold value for other purposes, and the recycling side is improving anyway. (Although there should be more legislation again to ensure easy recycling IMO)
Hydrogen may well evolve into a possibility, however I would hazard a guess it will be the hydrogen that will be a fuel cell powering an EV as opposed to hydrogen burning ICE style.
Due to the fact that whilst hydrogen being burnt directly is better than petrol and diesel on emissions it still creates some nasties that aren't generated when it powers a fuel cell.
I suspect fossil fuel zealots who think hydrogen will give them an equivalent are likely to be disappointed. Again the masses will not care, and will probably prefer the quieter, lower emissions, fuel cell approach.