You can read in the history books ( and I have) that these laws were pushed hard by the relevant professional associations. But the motives are a matter of interpretation. They aren't going to come out and say, "We want to establish legal education requirements so that we can make more money". The argument they make is that we need to make sure everyone is "qualified." Perhaps they were being sincere, perhaps not. But if even if they were wrong out of ignorance, the idea could out compete the truth because it has a built in ratchet affect.