First, Apple doesn’t allow upgrade pricing. Everyone would use it if they could. They can’t. That option is off the table.
1. I want to have very few subscriptions. I don’t want the financial commitment.
2. Almost no apps are valuable enough to me to even remotely make me consider subscribing. Fewer than ten. Maybe five?
If the answer is no (as usual), I just say, well, the App Store self-cannibalising model killed another app, how sad. Then I walk away.
I’d consider @culturedcode Things, @OmniOutliner, and @mindnode (which is going subs-based soon), depending on the non-subs versions/features.
I think that’s it. I looked through all my apps here, and honestly I could live without 80% of them, and readily find substitutes for a further 15%+. That’s fine. Market forces and choice.