Magnus Hansen fed off the Borg for a year, before he cocked it up.
Also the Borg harvest cities not mineral deposits.
Younger races are going to find all these planets that should be occupied, but are not. Empty planets to colonize with mass transit systems and an M-Class atmosphere.
Also, these younger races are less likely to be invaded by assholes like the klingons, because as soon as any species gets to a point where they might take over half the quadrant, they also have something that the Borg want.
The nigh certain assimilation of species with 24th century Federation level tech, lets the up and coming kids, with Archer level, 22nd century level Federation technology technology run around kinda care free without being picked on by bullies with faster ships and bigger guns.