The issue here is obviously not limited to air travel; There seems to be a story on a lithium battery fire caused by an e-bike, power bank or other device in the local press every day. Houses are burning down and people being injured - sometimes fatally - as a result of these cheap, often unstable products that have exploded (yes, see what I did there) in popularity and availability through the online marketplaces out of China.
Someone needs to come up with a legitimate way to certify and mark which batteries are safe, and for those which are not, we ban the import and use of them. All airlines should agree to the same standard, and screening technology identified by airport operations. The cost of power banks would likely need to go back up, but it's a small price to pay. I don't use power banks often, but they do serve a genuine purpose, and should be something that travelers could carry with them and use, assuming this safe standard can be reached.
Is any of this realistic?