It is indeed true that universities did not used to offer courses in immigration law. But we did have law courses that taught us how to interpret laws and regulations, which were often complex, in the field of immigration law. You can see here, I have the Canadian statutes annotated. The stack is quite hefty and does not even include them all.
It is also important to bear in mind the requirements of the bar. For a year and a half, lawyers in training study the law, learning how to practise and interpret it. They also have to article in a law firm under the supervision of a lawyer.
A lawyer is trained to be able to practise in more than one field of law. Universities do not produce lawyers so much as legal experts. It is only afterwards that you decide whether you want to be involved in politics or, in the case of Quebec, join the Chambre des notaires du Québec or the Barreau du Québec.
As far as a regulatory body for immigration consultants goes, I think it is really important to distinguish between consultants and lawyers, because the distinction is great. They are two totally different worlds.