>>63953341
Not really true. Humans were a more numerous and spread out species than any single covenant race. They had lots of outposts and colonies. Most of them weren't strong enough to hold out against a single covenant fleet, though. Humanity was perpetually losing the equivalent of foreign military bases. The battle for Reach was the first time that humanity really made a stand. It was their equivalent to Hawaii, the strongest place outside of the mainland. Half the navy was sent to defend it. As such, losing it was a big blow. Nothing short of the miracle that was Master Chief and Cortana landing on Halo - and the events that spawned - could have saved humanity.