Yes, but that's because Qualcomm and Samsung are about as incompetent at CPU design as early-2010s AMD was; their products have been 3-4 years behind the leading edge for the past decade.
This might change with Qualcomm's acquisition of Nuvia, but they're still going to take a few years to be comparable with what you can get in a 400-dollar iPhone/iPad and be unavailable in the sub-1000 dollar Android market (just like the Snapdragon 888- whose performance is on par with the 2nd gen iPhone SE- is today).
The Anandtech breakdown (https://www.anandtech.com/print/18871/arm-unveils-armv92-mob...) goes into detail on this. While all the cores are claimed to perform better at the same power draw, they draw less power if they have to perform at the same level as the previous generation.
Smartphones will use a combination of big (X-4), medium (A720) and small (A520). Since the small and medium cores are more performant and use less power, that opens up opportunities for battery savings. There could be loads where the larger core remains asleep while the smaller ones finish the job, since they’re more capable. Or the same cores do the job, but use less power.
So if you buy a flagship in a couple of years, the CPU will consume less power. The battery tech will have progressed as well. However, the screens might be higher res or higher refresh rate (120Hz instead of 60Hz). Or it might use a 5G radio that needs more power. So the net effect is that battery lasts about a day.
phone that couldn't last full day, lasted over 3 with about maybe 40% battery (idle and stationary but connected to wifi)
Sadly this will probably mean some apps will be able to steal more CPU time for doing telemetry and serving ads because the user won't notice a difference in response time and performance.
My Android is 8 years old and it was flagship at the time and I also don't remember anything being slow on it.
I have also low end Android phone - which is 3-4 years old, it was cheap like $50-$100 range and on that phone nothing really works and even when it was new it was quite slow anyway. But I keep it as a backup in case my main dies and I need some phone to put sim card in to be able to call people.