So just a few quibbles with this show.
Couldn't Q just send them home at anytime? Couldn't Q just obliterate the Borg? This applies to all Star trek series. Couldn't the 29th century star fleet guys with time ships get them home?
Q could easily do it, but refuses to. The 29th century guys already know how they get home, so why would they alter their own past?
It's like asking if Bill Gates could feed most of the people who can't afford food for a while by giving a couple billion dollars to do it. Most likely he could, but don't hold your breath.
There was something about the 29th century captain who said they monitor both space and time. When they were taken out of the 20th century, captain janeway asked if he could send them back to the 24th century but leave them near earth. I can't remember his answer exactly but it was something like it doesn't work that way or they still had things to accomplish in the delta quadrant or something.
As for Q, I can't remember that nonsense at all. The Q2 episode made me hate Q so much but before that I thought he was a very interesting character. Q's excuse was probably something about how humanity needs to do it on their own even though it was a being sort of like Q who put them there to begin with.
Honestly, the way they got home was *beep* and it felt like something to just wrap the show up quickly. Sort of like the way Eureka ended. They could've given voyager at least one spin off movie instead of beating the dead TNG horse and throwing Janeway into a minuscule cameo.