I shouldn’t pay because I’ve already paid. Price updates for the same major version in. Let new sales be your incentive to keep it up-to-date. Let a new version I actually want be my incentive to spend more money.

Subscriptions for software that don’t offer an external service put all the incentives backwards strictly to the benefit of the developer and expense of the user.

There’s no question why it’s a great deal for the developer. But nothing you’ve said explains why any user should buy into this at all.