You are comparing specs when you say how good iOS updates are on the iPhone 4. It's just another number to say "oh look at me I'm still supported by Apple". What good is an update if it does include the features of that update (Siri, Navigation, 3D flyover, picture during video, etc etc). The iPhone 4 has gotten all of the cons (slowness) with none of the pros (features).
Contrast to Android, features are updated from Google via the App Store. So if maps gets an update it doesn't matter the version number of the OS. You still get the features included with that update.
To be fair we should be comparing Nexus type devices as well. And I'll use my Motorola Xoom as an example. It was the first Android tablet. Not only does it still have great feature support but went from Honeycomb to Jelly Bean including the project butter update. I've been happy with it's support.
Btw I'm not saying iOS updates are bad, just Androids is different and has it's benefits too.
I do agree that comparing stock Android devices to Apple is a much closer race. I also commend Google for pushing direct updates such as Maps, hangouts etc without having to go through the carrier. That helped a ton.
The last Android phone I spent a lot of time with was the Nexus 5. It wasn't "bad" but it left a lot to be desired. Battery life was terrible and I just didn't feel like having to flash a new kernel or rom to get decent battery life.
There are some things that Android does better, but IMO, the iOS experience is far better for the things that matter most such as battery life, smoothness of operation, and reliability.
It's my opinion and there are millions that disagree.