[ricksharp]

Give equally among all apps used in a time period sounds like the best metric.

In fact, I would argue that some of the most useful apps might be ones that we use less - because they accomplished the required goal.

[KingOfCoders]

"we use less - because they accomplished the required goal."

Exactly.

[Fnoord]

This may result in applications trying to keep you hooked in, addicted, or having unnecessarily long processes.

Subscriptions make sense for dynamic content, and service. Fantastical and 1Password are examples of subscription-based platforms which were once buy to play (term from games industry).

However if you self host the data (you probably can and should) or sell your soul to the devil (Google etc) you paid for hosting. So a subscription for the software doesn't make sense from customer PoV. You essentially don't pay for service, compared to Disney+, World of Warcraft, or Netflix.