I mean, you are correct that building an entire rail line to a single farm to take the farmer’s kids to school would be extremely inefficient. We need farms, and farmers, and those farmers need to be able to get around, and the way for them to get around is personal automobiles.

But the argument “farmers need cars so we still need cars” is not really an argument in favor of auto-intensive infrastructure. It is a edge case, and we should design cities around the needs of the average person and make allowances for edge cases, not the other way around.