Even without the DE Voldy still had the support of (most) Goblins, (some) Werewolfs, and (most) Giants.
Every ying must have a yang, and he would have developed magical followers as well, but as devoted as the DE?
I think the DE existed to help the reader passionately loathe Voldy because of his perceived power, and how devoted they were to him.
They were strong (and dark) because of their convictions... although misguided to most.
Voldemort would not have had giants of his side without his death eaters to go out there and recruit them. Goblins didn't take sides. They just tried to exist peacefully during the time of war. I don't think that werewolves were on his side so much . . . Greyback was the only that I know of. I think that the werewolves pretty much lived underground away from people. _________________