Like I said: Somebody has to be in charge of time travel.
There were also many episodes where there were natural causes for timeline changes. The prophets changed the timeline as well. So that alone makes the idea of "being in charge of time travel" pretty ridiculous.
And the Q I forgot.
Actually, the Q are already in charge to make sure "all of creation" isn't destroyed. So any human attempt to "control" the timeline can just be snapped away anyway.
I think there's even a novel about that, where Q takes Picard on a ride to stop the universe from being just ended by a greater power.