Let's not get carried away here. Spock and Nero time-traveled from their era to their past.
One of the problem I had with the movie is, Nero travel backward, arrived in his own
past, and created a alternate timeline.
Spock traveled backwards and didn't arrive in his own
past, he arrived in the alternate timeline.
Shouldn't Spock have arrived, when he did arrive, in the past of his own
timeline? It seem to me that he should have.
... the movie First Contact, where the 24th-century Earth becomes borgified from the past but the Enterprise is unaffected due to being caught in the time machine's backwash. So there could have been any number of changes to the past, just ones that we haven't seen.
Prior to the Enterprise destroying the Borg sphere in the past, the Borg fired on the surface of Earth, killing and injuring people. Many of the people killed were people who worked on the warp ship.
These people would (obviously) do no more work on the warp project, and have no future children. I assume that Lily was one of the three people aboard the warp ship when it made it's first flight, that both Riker and LaForge were on the flight means (imo) that the person who originally was the third crewmember was killed (or injured), otherwise they would have been in the position that they were trained for. With only Lily having to be replaced.
Removing that many people from the on-going timeline, several of them talented warp designers and engineers, had to have had some effect on the future.