Oops, wrong quote. This is what I meant to respond to.
Everything that Thawne changed was from the present forward. It didn't affect anything in the distant past, when the Spear of Destiny still existed. So even if the Waverider didn't exist, anybody who had access to a time machine could literally travel back to 1916 (or any other point in time prior to the alternate reality).
Everything that Thawne changed was from the present forward. It didn't affect anything in the distant past, when the Spear of Destiny still existed. So even if the Waverider didn't exist, anybody who had access to a time machine could literally travel back to 1916 (or any other point in time prior to the alternate reality).
Here's a question about last night--if the Spear of Destiny changes reality, then time travel shouldn't be able to stop it, because reality must be altered in all time periods to get to the world these people want.
So somehow, Thawne would have been able to not have Eddie kill himself, which would preserve his existence. At least, that's the theory. For me, the only reason that time monster thingy was in the cage was because Thawne wanted it that way. He chose it.
That's why it was unclear how going back to 1917 would work. The reality where the Legends came from should not be accessible via time travel.
Time travel should be the solution, but it should be to a time before Thawne destroyed the Spear, which literally could have been a few minutes before he did so in 2017.
When Mick had the spear, all he had to do was use it to alter reality so that it's back to normal, except Snart lives.