why would someone include tech that makes people think twice about using the app, unless it is required if you want to "sell" in a particular venue.
if your developing geolocation based apps, location tracking is a core function.
a calender, absolutely does not require location tracking beyond what side of the prime meridian are you on.
But the subsequent sale of that data is not—is the discussion here.
you cant sell what you dont have unless you lie lower than a rug.
fix the data collection problem and a second order effect of no data for sale emerges.
Because the overwhelming majority of people don't think twice about this tech.
I do, and that's why I use a lot of web tools or old-fashioned phone calls, but most people think metadata=unimportant and assume that the purpose of the app is what it does for them rather than to gather their personal information for sale.
Even if Google and Apple both want to commit to fighting this, it becomes a game of whack-a-mole, because there are all sorts of different ways to track users that the platforms can't control.
As an easy example: every time you share an Instagram post/video/reel, they generate a unique link that is tracked back to you so they can track your social graph by seeing which users end up viewing that link. (TikTok does the same thing, although they at least make it more obvious by showing that in the UI with "____ shared this video with you").