In the past couple of years we've seen manufacturers use larger and larger batteries. Unfortunately, they didn't really do that to increase the battery life of our phones to 3 days or 2 days, or even a full day for people who are more active on their phones.
They did it to be able to get decent battery life with the much more powerful processors, and much bigger displays with much higher resolutions, than they had in the past. Some manufacturers even do all of this, without even increasing the battery size much or at all. And that's why the lack of focus on battery life, is going to either make our phones last less, or more expensive and slower to charge because of the bigger and bigger batteries we have to put in them. All of this needs to change, and manufacturers need to turn their focus on battery life first, and then on improving performance, resolution and so on.
We've already reached what I hope is the maximum resolution for smartphones, 1080p, which brings a mind-boggling 440+ PPI on 5" and smaller screens, which does make them look unbelievably beautiful, and I do think the screen should be as beautiful and sharp as possible, because that's what you're looking at and using all day, so it should be pleasant to use. But now that we've reached this threshold in resolution, manufacturers should work on making the screens more and more efficient, while never again having to compromise on efficiency to bring a higher resolution to the display.
Then there is also the performance of the processors they are putting inside these devices. It used to be that chip makers would make it their goal to keep the power consumption at maximum load the "same" as it was a year before, even as they increase the performance of the chips. This could be done through different optimizations, and by using a new process node. So let's say they were making it their goal to keep the power consumption at 1W, and then try to squeeze whatever extra performance they can get from the chip, without going over that 1W power consumption limit.
However, lately I've noticed the chip makers have made that goal a lot more flexible, because all of us kept asking for more and more performance, and they needed to "win" that race. So for example, instead of adding 20%-30% performance increase a year later at 1 W, they were adding 50% or more, for a higher power consumption. And every year they've started compromising on power consumption, just to get ahead in performance.
So now we've reached the point where these chips can reach even 2W, 3W or more when under maximum load. This shouldn't have happened, and they should've always made strict efficiency their main goal. But it did happened. So now it's time to slow down the performance race, which many are starting to believe is not so important anymore, as the devices are fast enough, and there aren't even that many apps to take advantage of all this performance. The focus for chip makers and phone manufacturers should be to get this performance at 1W or lower now.
Then, when the displays are as efficient as they've ever been, and the processors are the same, the big batteries we're using in our devices should start to give us much bigger battery life than what we're used to these days.