In most cases, the pastureland for cattle for meat isn't suitable for growing anything more than grasses or may be inaccessible for growing other human consumable vegetables.

https://www.google.com/maps/@44.715929,-106.2792854,3a,75y,1... falls in the agricultural land category.

In the "what should we be growing" it is important to separate Iowa from Wyoming.

For much of Wyoming, the best land -> calorie conversion is through cattle.

Trying to farm Wyoming for human consumable vegetables leads to other issues such as growing season, depleting aquifers, and salinization of the soil.

This isn't to say that cattle don't have problems - but its not a simple "switch to farming plants to feed humans" in many areas.

Animals are part of ecosystems, and play a role in their health and sustainability. The great plains are fertile farmland in large part because of Bison.

The problem we have is that animal products are more profitable in general than vegetables, so people overproduce them. It's the same thing behind the housing crises we see everywhere - luxury apartments are more profitable than low income housing, so that's the vast majority of what gets produced even though it's not what is needed, and it just fuels speculative buying.

"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.