As well, while on my original HTC G1 I optimized the thing to an inch of its existence, with modern phone there is SO much happening in background, I don't even know where to start so I give up and have literally bought couple of 10-packs of charger wires, and have wireless charging pods in several rooms.
I miss the days of my Palm Treo, when I could take it on a vacation and not bother with charger :P
More power does not translate to faster experience, it translates to less efficient software. More battery life translates to doing more wasteful things in the app, optimisation is not considered "worth it" anymore.
Related, even if not directly referencing battery life or Android: https://news.ycombinator.com/item?id=30442529
In the same vein, I use Photoshop CS2 because it works in Wine, the licenses were distributed for free by Adobe themselves, and specially because it has most of the features I would want from PS.
While batteries keep growing, we keep increasing screen sizes, pixel density, refresh rates... I believe 5G also consumes more power.
On my last phone, I had a few apps that were power hogs, but I'd say that's more poor design by their programmers.
The two misbehaving apps I use at the moment are Google Fit / Google Earth. Even after I finish my workout it drains the battery, as indicated in Settings -> Battery. I have to force stop them manually. If Google can't write a behaving app, after all this time, isn't that indication of some fundamental flaw in the OS ?
We also tend to use our phones a lot more than we used to, so they spend more time in a given day in active modes rather than standby ones, and many people have more background apps checking for updates than they used to, so there are extra short periods of CPU wake time, and radio activity, when the device would otherwise be in a lower power standby state.
SoCs being more powerful will have an effect too, but they are also getting more efficient especially when not in full use, so I doubt that this is significant compared to the factors I mentioned above.
Is that actually true? Five years ago it seemed like every phone had a QHD screen with some 4K options. Now most phones are 1080p, or are set to run at 1080p despite having higher resolution screens. The best phone display I've ever used was the 2560x1440 beauty on my Note 4 and I'd kill to get another phone with a QHD 16:9 OLED panel.
It seemed to be the last couple of times I was researching new phones. Though there is a significant caveat there that I don't buy top-of-the-range flagship devices as the hit when I break them is too high, perhaps the difference does not carry to the really fancy devices with all mod cons because they have more expensive but more efficient screens? The other caveat being that I'm going by 3rd party tests: this isn't something I've verified with my own study.
As mentioned above, overall tech could play a role in some larger and/or higher res screens doing better than they might compared to other models wrt battery life: IIRC Samsung use AMOLED screens which are generally more power efficient than the screens that might be used in my price range?
Install LineageOS but skip "GAPPS" (Google apps), don't install nosy background-active spyware like Facebook and its ilk and you should be able to easily go beyond 1 week on a device with a 4500mAH battery with "light usage". in full colour, with normal functionality. Standby time of up to a month (I got 21 days on a Motorola Defy with a 1700mAh battery), "normal" charge interval of twice per week with normal use. I would not buy a device which needs daily charging.
Too much demand so phone makers have to use shittier batteries.
Anecdotally, I have an S10 and in the two years I've owned it, it's gone from finishing the day with 30% left, to having to charge it 1-2 times a day. I've never had an android phone reach this level, my V30 would still get to the end of the day at 0-10% after two years.
Also purely anecdotally ofc but my 3y old S10 still finishes with 10-20% left at night, and I'm using it heavily for browsing during the day (FF+Ublock). I do have some power saving settings enabled though, and disabled fast charging (since it charges over night anyway).