The whole issue might come down to simple practicalities. Who's going to teach PPLs in the future? CPLs are being fast-tracked to the regionals nowadays, which is putting considerable pressure on flying schools to find new instructors. Those who are still taking the instructing path are only doing it to build hours. If you were to give a young CPL the option of going instructing or straight into a multi-engined job, where do you think they would go?
Yes, there are some career instructors, but not very many at all. Then there are the small group of "amateur" CPLs who spend their weekdays earning real money and their weekends teaching flying. But if you take away all the instructors who are hour-building, there are not enough left of the first group to teach in the smaller schools.
I restate my question thus: if not PPLs with an IR, who's going to teach PPLs in the future?
Walrus