[gruez]

>I would believe this - after all how many billions of dollars did Google pay Apple to be the primary search engine on iOS?

The OP also mentions Facebook and Spotify also are violating rules, and to my knowledge they're not paying apple "billions", so this explanation doesn't pass the sniff test. The actual reason is probably far more banal: these apps command a huge user base, which would be very upset if apple banned these apps. As a result apple is letting such infractions slide because they don't want to upset users.

[burnerthrow008]

Could also be that they are afraid of more antitrust attention if they enforce the rules too strictly.

The EU already handed Google the browser market on a silver platter, under the guise of “competition”. How much farther would they go if Apple prevented a perceived competitor from abusing users?

[MBCook]

They’ve done this for years before the EU started stepping up.

I think a more likely explanation is they know what would happen to their sales numbers if they kicked off Facebook and Spotify.