In 2013 I finally left behind my trusty Blackberry and got an android phone. I dont remember what model, but I do remember being unimpressed with the gradual slowdown it developed with age. So I switched to an iPhone and was content. Fast forward to last August. I gave my iPhone SE to a family member that needed a phone ASAP and picked up a NiB Samsung S8 Active which I am currently using. Just like my first Android, this one is showing signs of slowing which I think is somewhat odd. I asked friends that have Android phones about this gradual slowdown, and most have said they've noticed it too. What is the technical reason why this problem hasn't been solved yet?