Apple

I'm still not seeing any reason why Apple should have an advantage here. Any Android OEM should be able to walk up and make a great hardware pairing with the open source Android OS. But they don't. Instead they rely on Moore's Law to keep them afloat.

Couple things that should be mentioned... First, iOS runs apps natively. Additionally, Apple uses Swift as their language for apps, which surprise surprise, was built by them for their products. Android has some overhead with JVM (virtual machine). Unsurprisingly, this means it may take apps slightly longer to open (though not always the case), and use a bit more memory in the process.

Second is background processes. Android tends to have additional processes (which depending on the skin you use will be different) for widgets, backgrounds, app services, god knows what else (depending on the apps/skins used). Apple is fairly conservative, meaning less memory usage.

I have an iPhone 12 Pro (6gb of RAM), and a Galaxy s10 (8gb of RAM). iOS (according to some system status app) is sitting at about 50% (roughly 3gb) with only Memmy (and the status app) open. Android is sitting at just under 50% (about 3.5gb) with Jerboa and the settings app open. I've also taken a look at my Galaxy Tab S6 Lite which has 4gb of RAM, and with Twitch open in split mode, it's at roughly 65% (2.5gb).

So, not surprising that modern Android actually doesn't use all that much memory compared to iOS. Would I still say iOS is far more optimized than Android? Absolutely. But that doesn't mean that Google and manufacturers of Android devices don't care about performance. Millions of people wouldn't be using their devices otherwise.

As you mentioned though, that doesn't stop random companies from building shitty products. Horrible performing devices like tablets, budget phones and tv boxes exist. Just the nature of open source.

Also, almost every device user, be it Android or Apple cares about specs. Camera, display, size, etc.. RAM just isn't a thing Apple users need to worry about because memory was always managed so incredibly well, while Android in the last did have memory issues.

This whole debate of iOS and Android doesn't mean all that much anymore in the flagship space because both perform very well.