You must have a very very cheap or an especially buggy Android phone.
Having used both Android and iOS I think it's quite clear that both platforms are just as buggy as one another with the recent iOS11 outpacing Android in terms of bugginess by quite a large margin.
When you buy an iPhone you are paying for the build quality and for the marketing, you are not getting an objectively 'better' phone.
You also pay for proprietary operating system. Which is a main differentiating point of iPhones. I have used all types of phones (iOS, Android, Windkws Phone, Symbian). Apple has the best operating system. It has superior UX, is most user friendly and has deep vertical integration with other Apple products.
That’s worth a lot of money to most users. I think more people are willing to pay premium to get the great operating system compared to hardware which might be secondary.
All of that is very subjective (and why do you state this as a 'fact'?).
If you don't use Apple as your main computer you basically have zero integration. Don't even get me started on interoperability (you can't even use the iPhone headphones on a mac??)
That the UX is superior is also highly subjective. There are many things that are either impossible to do or a massive pain to do on an iPhone; I would not consider that good UX (for example try looking at a picture you just took on your camera and apply some filters before posting it to instagram. The only way I have found to do that is to open instagram and open the picture in that app. The notification system is a massive joke. There are dozens of other such examples).
What is worth a lot of money to users is convenience and habituality. Having to change your habits, workflow and frame of mind can be quite taxing for some people.
Having used both Android and iOS I think it's quite clear that both platforms are just as buggy as one another with the recent iOS11 outpacing Android in terms of bugginess by quite a large margin.
When you buy an iPhone you are paying for the build quality and for the marketing, you are not getting an objectively 'better' phone.