A poll conducted by GSMArena suggests that Android Auto is used by 50.1% of car owners, while only 17.4% use Apple CarPlay. No insight into the “I use my phone with a holder” camp is given, as they could be Android or iPhone users.
Other poll results are below:
If your purpose is to side load apps that aren’t in the official store, customize OS level ui elements, or replace built in features then yes.
Changing the UI elements isn’t the reason why Android exists. The purpose of a phone’s OS is to act like a phone. Both Android and iOS do this perfectly well. If they didn’t, nobody would use them. Everything else they can do is just a nice bonus.
Don’t get me wrong, I much prefer Android because of those features (plus I hate walled gardens), but I think your usage of the word “purpose” might be a bit of a stretch here.