[ggm]

This will cut revenue. If twitter-class apps move, and if Apple cannot contract enforce the 30% cut on some component of payment. So, I expect some reaction in terms of future earnings from this.

This will weaken the defences of the walled garden, unless Apple mark-sweep the 3rd party stores. If you value a walled garden, and some people do, then the walls got lower. This isn't necessarily good.

I expect to see ringfences go up: Safari and Mail and like apps may well stop doing open file on content from side loaded apps, if they can't prove they are safe. (proof.. whatever that means)

[compsciphd]

twitter class apps on android can be sideloaded today. What %age of users actually sideload them vs getting them through the play store. i.e. how many of these apps actually provide an apk to install directly.

[ggm]

I sort of get what I think is your point, user behaviour here is probably modelled on what happens in a domain similar to the one under discussion.

But Apple experience has been far more constrained and it's single source with almost no prior of sideloading. They're a different set. I am less sure how any sideload in Android or install alternate marketplaces is informing, maybe it's the best information we have.