I think your assumption is too optimistic. The only way the market would correct itself in this situation is toward user hostility with easy signups but hard cancellations (e.g. New York Times). So yes there will be some market correction, but only in ways that increase sales at the cost of user tolerance.
That said, I don't think Apple should be the one to fix this system. The government should prevent such harmful behaviour through legislation rather than relying on private parties.
Besides, users can always choose not to pay for items in their apps if they can't use their preferred payment processor. People living in places where this predatory behaviour is still legal can choose not to pay through payment providers that don't allow them to easily cancel for the extra fees those providers (like Apple) charge.