Hasn't it been common knowledge for like 4 decades that throwing more bodies at the same problem is grossly inefficient? I can't imagine that 4 folks sharing 1

Hasn't it been common knowledge for like 4 decades that throwing more bodies at the same problem is grossly inefficient? I can't imagine that 4 folks sharing 1 keyboard would result in as much or even as good code as 4 people in 2 groups with 1 keyboard each?