I've been recording the current draw from my s6 using ampere- the absolute lowest i can get is 100mah (screen at minimum brightness and airplane mode). The highest is around an amp with the screen on.
This means that my phone would be flat in two hours of use, and likely sooner. I typically get 5 hours of battery life out of my phone- which to me is ridiculous: just listening to Spotify for an hour in the gym and a 40 minute commute, and I am down to 50% from a full battery (screen isn't on all this time). I have tried factory resets and it is not significantly better with even the stock apps.
I know that power management comes into play when it comes to battery life, (especially during idle times), but what makes modern smartphones so power hungry? Is the screen the main culprit? or just crappy unoptimised apps that keep the device awake?