Have you looked at the criteria for a student Visa? First you have to have $10,000 in the bank for every year of study. That plus you need to be accepted at a certified institution and pay for enrollment.
Also, they ask for the level of English on an international scale and you must be in the top tier to be allowed to study. My wife speaks English well, even conversational but she couldn't pass for the level they require for study.
Many obstacles plus just to get approved as a student, then you have to go through the PR process once she's in the country anyway but that's not possible.
We're 6 months into this process now after all of our troubles so now we wait. Another added benefit to the PR process is that there's an appeal process if rejected. The Tourist or Student visa is an outright refusal. Case closed.