Hate to completely disagree, but I do. For one, you seem to love the Borg from your quote, so you may be biased. You should also remember that in that same instance the Borg ripped through 27 aged defense vessels; the Sovereign-class Enterprise-E showed up it ripped right through the Borg Cube like tissue. Besides there is no evidence that the Borg originate technology. So I'm not so sure how you could say that they advance faster, since I can find no cannon evidence to support it. They assimilate; they don't originate. The fact that fractal based encryption can boggle the Borg, show an unoriginal kind of thinking and it takes original thinking to innovate. It takes innovation to advance technology. Since there are several instances in the Star Trek mythos that show more advanced technological societies existed, the Iconians, the Hus'noq (maybe), the Hurq, the Preservers, etc., the Borg could have been their contemporary. So it can also be argued that the Borg reached their pinnacle of their technology BEFORE becoming a joined cybernetic entity and have not advanced since, other than by assimilation. Sorry to put things in a different light.
And finally, once outside Trek cannon, they get to make up whatever reasons they want.
You make an extremely good argument. My point was not that they originate, but that in so far as we're fighting them, they should have already adapted and can understand and emulate all of our technology. In that they assimilate, they are, by default, just as good as we are at their worst. Also the Sovy isn't what ripped through them, it was Picard. They had no shields, murdered 27 ships and were just about to kill the Defiant, an experimental warship that could take out Galor class attack cruisers like tin foil. This warhound had been ******g (wait what? you censor dogg ing really? now people will think I said something vulgar and completely different... add the prof filter on these forums to my list of short tem fixes) them for lightyears in a prolonged two hour encounter with thirty other ships.
Also in endgame recall that Voyager decided not to use transphasics, and later starfleet agreed, unless it was approved and deemed an absolute last resort, because every time they shot them with it the borg were one step closer to adapting and making their new toy worthless like so many other federation weapons against the borg.