This was mentioned in another episode..Shattered.But Janeway could have gone back to the events in "Caretaker" and used the advanced weaponary of the shuttle to buy her younger self the time needed to activate the return mechanism on the array, how many of her crew lives would she have said then, sure there was a risk that some would be killed or injured activating the array but there was a risk some would be killed or injured trying to destroy the transwarp hub. But of course that early on they hadn't picked up Seven yet. Janeway's action where in part selfish because she lost friends along the way Seven and Tuvok in a way. So what if other people had lost friends/family in the seven years since arriving in the DQ and using the transwarp hub.
Speaking about the transwarp hub, it had an exit fairly close to Earth, so why didn't the Borg use it to send vessel or two (hundred) to assimilate Earth before Starfleet could react. Why not have the exit point somwhere near Ivor Prime for example.
JANEWAY: I can't let this happen. Not again.
CHAKOTAY: What are you talking about?
JANEWAY: Voyager getting stranded. All these deaths, this entire future, it's my fault. I've got to do something to change it.
CHAKOTAY: What do you have in mind?
JANEWAY: Maybe we can find a way to modify Seven of Nine's plan. Put Voyager into temporal sync with my timeframe.
CHAKOTAY: Captain.
JANEWAY: Now that I know what to expect, I could avoid getting trapped in the Delta Quadrant in the first place.
CHAKOTAY: Halt turbolift. Seven's plan is dangerous enough. Trying to alter it is too risky.
JANEWAY: It's worth the risk.
CHAKOTAY: If Seven's idea works, Tuvok and the other crewman will be fine.
JANEWAY: They'll still be stuck in the Delta Quadrant. If the temporal anomaly doesn't kill them, something else will. The Borg, telepathic pitcher plants, macroviruses. The Delta Quadrant is a death-trap.
CHAKOTAY: What about the Temporal Prime Directive?
JANEWAY: To hell with it.
CHAKOTAY: With all due respect, it's a little presumptuous to think you have the right to change everyone's future.
JANEWAY: From what I've seen, they'll thank me.
CHAKOTAY: All you've seen are bits and pieces. You're not getting the whole picture.
JANEWAY: Really? Just what am I missing?
CHAKOTAY: It's not what, it's who. People like Seven of Nine, a Borg Drone who'll become a member of this crew after you help her recover her humanity. Or Tom Paris, a former convict, who'll be our pilot, chief medic, and husband to B'Elanna Torres.
JANEWAY: That angry woman I just met?
CHAKOTAY: She's going to be your Chief Engineer. Two crews, Maquis and Starfleet, are going to become one. And they'll make as big a mark on the Delta Quadrant as it'll make on them by protecting people like the Ocampans, curing diseases, encouraging peace. Children like Naomi and Icheb are going to grow up on this ship and call it home. And we'll all be following a Captain who sets a course for Earth, and never stops believing that we'll get there.
JANEWAY: Are you going to be lecturing me like this for the next seven years