Whelp - I feel like you’re overestimating how much money people donate.
I’ve got a website service that I offer for free with a Kofi tip jar - I got less than 20€ over the past 3 years that is was online. Which doesn’t even cover domain costs.

Sure it’s very much not in your face and it isn’t meant to be, plus being only one anecdotal point of reference, but that’s just my experience with that.

Understandably - as a developer you need to pay money to keep your apps listed on the Apple store - even if they’re free apps. So just to recoup those losses you almost have to put in ads or subscriptions.