When I used a Pixel 3a with LineageOS, I recall never having to think about battery life unless I didn't plug it in overnight, and even then, it would survive just fine for a second day, it would just be at like 20-30%?
I used to have a iPhone 6S Plus and when the camera died, I decided I wanted a more private phone. I opted for the Pixel 4a 5G and installed Calyx OS.
I absolutely love Calyx, and wouldn't move from it. However, the battery life even compared to my old iPhone 6S is pretty bad. I'm not even a heavy phone user, I don't use social media or have many apps sending me notifications (only Signal) and I feel like my phone can't even last two days of light usage. My iPhone I could use similary and I could usually get 3 days of usage.
How are you getting 3 days of usage out of an iPhone? I don't use my iPhone X much at all (mostly texting and occasional web browsing), but I'd be lucky if I could get 2 days out of it. Meanwhile, my last Android phone would consistently last 3+ days on a single charge.
(To be fair, I ran LineageOS without Google Play Services installed, which makes a huge difference, so it's not exactly apples to apples.)
This mirrors my experience, but it does not invalidate the parent's statement.
Specifically: While iPhones are noticeably more power efficient than Android phones the latter have been sufficient for my usecases especially given that there are typically options with larger batteries.
I agree that quantitative metrics would make for a much stronger comparison than a few people's subjective experience using both kinds of devices.
In absence of that, even an anecdotal comparison seems more relevant than a statement that only considers one of the two items being compared.
Update: Because I was curious whether my subjective experience was backed by real numbers, I looked up the top few Android and iPhones with the greatest battery life as per the first website I found [1] and calculated their efficiency based on their battery capacity. Various iPhone 13 models used 3.1 to 3.6 mAh per minute whereas the Android phones used 4.0 mAh/min (Moto G9 Power), 4.2 mAh/min (Samsung Galaxy A03s, Realme 9 Pro), 4.3 mAh/min (Nokia G21).
I absolutely love Calyx, and wouldn't move from it. However, the battery life even compared to my old iPhone 6S is pretty bad. I'm not even a heavy phone user, I don't use social media or have many apps sending me notifications (only Signal) and I feel like my phone can't even last two days of light usage. My iPhone I could use similary and I could usually get 3 days of usage.