So far with every upgrade they have added features like more powerful processors and power hungry higher density screens. So most people haven't noticed the improvements in battery tech. Now I think phones have reached a point where I don't see many power hungry improvements going forward so we might start seeing longer lasting phones.

> power hungry higher density screens.

That is not exactly true. OLED can be very efficient. Not just in Dark Mode, but you need to be aware of those pitfalls and optimise for it. Since in overall package the Display is roughly the same power but you get much better quality.

Not to mention there are at least 3 - 5 years roadmap of technology in the pipeline that makes it even more energy efficient and thinner. ( Thinner equals potential for larger battery )

The higher density screen might need to require less power but the power to display on them used by the graphics etc is a lot higher. we were on 320x640 screen now we are at 3840 x 2160. Even if the individual pixel takes less power the number of pixel has gone up a huge amount.

I used to charge once a day (10 years ago), and I still do because my phone can't last 2 full days on a full charge... but it does last about 1.5 days ... it is not an iphone 11 but it is still an $800 phone

The number of hours you spend and what you do on your phone today compared to 10 years ago is also not the same.

That's not true in the slightest. Energy per instruction varies a lot but has not decreased that much on recent nodes. The resistance growth just outpaces the shrinking capacitance of the gates.

On top of that processors are faster, applications and sites are hugely more intensive to render, and the hardware (mainly antennas) suck up much more energy.

The ARM11 in the iphone 3 used <1 watt. The A13 in the iphone 11 uses 6 watts.

Back when I had a basic phone I charged it roughly once per week.

But of course modern smartphones do a lot more, and I spend lots more time with my smartphone as well.