While apple maps certainly isn't the greatest, if I have to use google, I'll just click on that app. What a consumer desires and what apple will provide are two different things. I can't imagine why they would let you choose to prioritize someone else's apps over theirs (ones of real value like or whatever). It's nice to ask, but you pretty much signed that right away when you bought the iPhone.
Apple would let you prioritise someone else's app over theirs because maps make them no money, but having to use their Maps as a core OS feature makes their hardware considerably less attractive. Which doesn't make money for them.
In much the same way Apple let me install Windows on a Mac.
To be blunt, over the years Apple have added a bunch of stuff people have set there and defended as "un-needed by the general public" until Apple put it in, when people accepted that actually it was always needed after all.
A background downloading API (which someone told me Apple would never do on this board less than a month ago IIRC) was one. Quick access to the settings toggles another. A notification centre before that. Running third party apps before that.
The last three major things where that's true are a centralised file storage that can be shared between apps, changing the default apps and multiple user accounts. They are necessary. Apple will even do them eventually. But it's too late to defend their absence.