Because it takes so long for Apple to correct its course of action? By offering the tool, Apple admitted that there is problem with iMessage. However, Apple did not do anything for years.
Or maybe they were trying other solutions and finally came to the conclusion that this was the only one that worked. You don't know if they did nothing or not. Only Apple's engineers know that.
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Looking forward to my portion of the settlement. While I happily own an iPhone 6, it was ridiculous for apple to allow this to happen. There was nothing in the iMessages welcome message that informed a user you were tied to their service. In fact, upon iPhone activation it automatically enrolls a user in iMessages. I ran into this issue and is one of several things to causes a little hate toward apple.
Enjoy your 2 cents. The lawyers will enjoy their millions.