it is a little disappointing that public health didn't act quicker - lots of people have been overweight for a century now, so literally 10's of millions of people could have been saved from dementia had action been taken 100 years ago

Given that the drug did not exist until only recently and it took decades to develop with the latest of technology, I don't see how this could have been possible. Stomach surgery has been around for 50 years though, but it's a bigger undertaking than an injectable drug.