No-one eating honey, no bees - simple. Of course there would be wild bees, but in much smaller numbers so insufficient for the pollination of food crops to feed vegans. Beekeepers make sure their bees have enough food for the winter, otherwise they'd all die off.
Similarly, if no-one ate eggs there'd be no chickens (assuming the meat isn't being eaten). The eggs we eat aren't fertilised, so we're not 'killing' chicks.
If we didn't drink milk or eat meat, there'd be no cows, sheep or pigs. The system wouldn't be balanced and sustainable.
But food production should be as kind as possible to both the environment and animals.