There are more non-fruit bearing than there are fruit bearing trees. It's a safe assumption to consider early ancestors, prior to becoming land dwellers, had the largest portion of their diet based from leaves.
That's a keen observation. Prior to shifting from herbivores to scavengers, the apport of B12 would probably be obtained from specialized intestinal biome. Since evolution always comes with trade-offs, that was a loss in the long term.
I refuse the insistence with humans being obligate carnivores. Prior to becoming active predators, humans widened and improved their diet by including what they could scavenge from the landscape, including meat sourced from dead animals or abandoned predator kills. That is actively developing and evolving into omnivorous capabilty.
Eggs are not meat. Eggs are an animal product, granted, but it's not from its consumption we derive the notion of being carnivore.