Geekbench is flawed the only reason the iPhones score higher is because of optimised HTML test.if you look at the snapdragon 820 is scrored like 500 in that test and the iPhone does like 30,000 and it majorly boosts it's single core numbers.
the 820 scores 22-2300 in geekbench 3 and in geek bench 4 it drops to like 1500 because of that little test they added to boost the iPhone.
apple owns the browser and has that test optimized to scrore high.
Apples chips score well beyond Geekbench. They are powerful mobile chips and they deserve credit where It's due.
How much more powerful they are however is overblown. Software plays a large role (look at the pixel as prime example of a perfectly snappy OS - snappier in my experience than iOS 10 on an iPhone 7 is) as does optimization, and also iOS is displayed on much lower resolution devices than most flagship android counterparts, less pixels to push with a powerful chips leads to these kinds of larger discrepancies.
The reality is modern smart phones offer more than enough power for basic "single core" functions like texting and making phone calls. You can still do that stuff with much weaker phones more or less lag free. Even an iPhone 4s running iOS 9 is capable enough for those functions.