Putting on my Older Person hat for a moment, software from indie publishers used to cost in the ballpark of $40 in the late 1980s (that's ~$100 in 2024 dollars after adjusting for inflation). $100 for a single version of a single app. When the next point release comes out, the publisher might give you a discount of 50%, so it might only cost you $50. A major release was often required for compatibility with a new OS version.
All the software we used back in the day? We spent significant money on it.
Do you think apps like these pomodoro apps would sell in sustainable quantities if it were $100 for major releases and $50 for point releases? What if it were $100 to get the current version every time iOS did a major version upgrade?
Or is it more likely that these apps would simply not exist?
People say they want one-time purchases, but the small $ subscriptions are more consumer-friendly than is immediately apparent. And they support a vastly more comprehensive software ecosystem.