One issue is: when the Reminders app was simple, making a better reminders app just had to be a little more complex that a single developer could improve upon it and charge for it once and make a living. Now, the bar is so high, that it takes significantly more work/time to make a better app, and thus we have to pay subscription pricing in order to use it.

Instead of: let me buy this app for a few bucks and give it a spin, its now: even if I like this app, do I want to pay for it a few bucks a month for forever?