This is happening with a lot of companies that don't really have to care about "startup value"; they're tiny (sometimes even one-person) shops that aren't likely to ever go public, be bought for millions, or so on. I think you've got the cause and effect reversed for a lot of these -- the App Store pricing model has driven the price people expect to pay for apps down substantially, which made the "buy outright and then buy a new version in a couple years, at a discount, if it appeals to you" model much harder to sustain. I don't love subscriptions for apps that don't have a server-side component, but I get it.

(The example of the Pomodoro app with the subscription is pretty dubious, though.)