1.The market is completely efficient. As soon as an app is released, every user has noticed this, and considered whether to purchase it.

2.Once someone has considered purchasing a piece of software, and rejected it, they will never consider it again.

3.Only people new to a platform buy software.

4.A small indie developer can easily saturate their market.

5.Mac App Store customers are used to paying for software upgrades.

6.Software developers can only survive without upgrade pricing if the platform has hockey stick growth.

7.Software developers rely on upgrade spikes to survive, because — at other times — they have no sales.

8.Software developers earn most of their income from sales spikes associated with an upgrade.

9.Writing a new app is just as fast and easy as adding features to an existing app, so there is no motivation to upgrade software without upgrade pricing.

10. Upgrading an app can only generate income via existing users. There are no other advantages to upgrading an app.

11. It is more useful for a developer to spend their whole life adding features to one app than to develop multiple apps.