What would be the point?
It would generate NONE of the excitement. The whole point of Breaking2 was to see if they could break a time barrier that many said could never be run for a marathon. Now if they said "Breaking2:10" or something, I'd be interested.
A more interesting question is...Would Kipchoge have broken the WR by as much as he did, if he didn't have the knowledge (ie fluid intake, proper mix levels, running form, etc) and technology innovation gained from the Breaking2 project?
To be fair, the OP didn’t saying Breaking2:15 was actually happening. It’s a speculative exercise. That being said, I think 2:15 is still a cool barrier to break (like breaking 3:50 in the 1,500 or 14 in the 5,000, etc.).
To your Kipchoge question, I don’t think he would’ve ran 2:01:39 without Breaking2. Not sure if he would’ve run 2:01-high, but my guess is he wouldn’t have broken 2:02 without the experience, training, and whatever else they did to help get him there.