"Would this still be a problem if we didn’t use most of our agricultural land to grow crops to feed to the animals we eat?"
It depends on the lifestyle. If everyone agreed to go vegan and eat unprocessed food, and we stopped using crops for many industrial uses (ethanol, plant based plastics, etc), then just maybe. However, people want their plastics and there is pressure to move away from petroleum in the long term. My guess would be that plant based industrial products will readily take the place of any reduction in agricultural feed over the next 30 years. And of course this doesn't address convincing the majority of the population to go vegan, which would be the bigger challenge.
It depends on the lifestyle. If everyone agreed to go vegan and eat unprocessed food, and we stopped using crops for many industrial uses (ethanol, plant based plastics, etc), then just maybe. However, people want their plastics and there is pressure to move away from petroleum in the long term. My guess would be that plant based industrial products will readily take the place of any reduction in agricultural feed over the next 30 years. And of course this doesn't address convincing the majority of the population to go vegan, which would be the bigger challenge.