It was one of the reasons I switched from Android to an iPhone. It's really annoying to use Android if you don't want to use Gmail and Google Calendar, while on iOS it's super easy to use a third party for email, calendar and password manager.
But that's of course just an anecdote, I'm sure you're right and it in general bad for business.
I've run an Android phone without any Google account at all (something that's not possible on iOS), using a combination of FDroid and Yalp to work around the lack of Play. The fact that this is possible lulls people into this idea that Google is more open, but the reality is it's pain. You're locked out of many basic phone features, notifications are flakey, many updates don't work, and once you do opt into a Google account it invades every part of your phone's experience.
At least with iOS I can sign up for a fresh empty apple account and it leaves the rest of the (admittedly limited and very locked down) phone to me.
Apple is in a position where they can't expect everyone to be happy with iCloud, which is great because it means they actually put effort into supporting (decently!) a range of third party services. Siri generally isn't as smart as Google Assistant, but it also isn't completely obsessed with Google services. That is to say, unlike Google Assistant, every app on my phone - without exception - actually knows what is on my NextCloud calendar. And it actually gets useful information from my email to do helpful things with.
On the other hand, if you look at how Android has progressed over the years, I think Google has been trying very hard to forget about Android's past as a flexible operating system that exists outside of Google's ecosystem.
They don't even try with the stuff they extended android with, Android Wear and android's Daydream: no third party stores allowed, only loading via ADB.
And uninstalling an app is impossible on stock Android, if that app is made by Google.To achieve that I had to unlock the boot loader of my phone, for which there was no official method.
Meanwhile on iOS I can use the default mail and calendar apps that work fine and my password manager integrates perfectly with the os, while I don't need to use iCloud at all if I don't want to.
Those 3 apps weren't the only reason to switch from os, but they did make the choice for, and switching to, iOS a lot easier.
You need to find instructions based on your specific device. Each one is different.
GrapheneOS.org
