Why would the kid want to sacrifice himself to restore a timeline that never existed? Maybe if things get even more fubared in the altverse I could see that being an option, but Picard said it well in Yesterday's Enterprise.
"Who's to say this history is any less proper than the other?"
That was even when he lived in a messed up universe. But really even if NuTrek is a pale imitation of the prime verse in my opinion, it needs to define itself as it's own rather than just tying back into the prime universe at every opportunity. Jest let Spock Prime die of old age or something and get on with telling their story... hopefully one that isn't a rehash of something already done before.