I wonder what it is you're doing on your phone that you have this need for speed.
My LG V20 is super speedy for what I need: surfing the web with several windows open, writing email, downloading the occasional PDF or spreadsheet, taking and looking at pictures, occasional youtube videos and once in a blue moon Netflix viewing, with a handful of occasional games thrown in. Sure, it's a new phone but I was equally satisfied with last year's V10, the Galaxy 6 before that, the Galaxy 4 before that and the Galaxy 2 before that.
It's like complaining about Ulv chips used in ultraportables. Sure, there are those that will definitely need a fast quad core i7 chip in a large chassis with huge fans and a graphics card but for many people a low voltage dual core i5 is more than fast enough especially if it means a thinner, lighter case you can toss in a bag without breaking your back.