Little history reminder: For many, many years, PPL's with 150 hours in command could take FI courses and thus instruct. They were also allowed a salary to do so. I was one of them, but then in those days I had no intention of gaining a CPL, let alone an ATPL, I just wanted to instruct at weekends at the local club. I think I did a good job: my FIC course not only included the passing on of handling skills but also honed my theoretical knowledge beyond that of the PPL syllabus.
Often I noted at my club newly qualified instructors joining, demanding tons and tons of flying and when their logbooks contained the magic 700 hours, off they would go to get their CPL's without having to incurr the cost of an "approved course". We never saw them again, just had to sort out the instructional mess that they had left behind. Of course, because of this, the pay that part time FI's could get was peanuts (it still is) and there was concern that the poor wage structure discriminated against the "career instructor" discouraged high quality instruction and only favoured the hours builder.
Thus the requirement to hold a BCPL was introduced to try and cut down the number of hours builders and encourage the industry to pay a worthwhile wage to instructors. This did not solve the problem, thus the requirement to hold a full CPL was introduced for the same reason. Unfortunately, as there was such a shortage of flying jobs, the guy with a (say) 300 hour CPL was much less likely to get the coveted RHS job than the guy with (say) 1500 hours. Thus the brand new CPL goes off and gets an instructor rating, once again to build hours! To this day therefore the laws of supply and demand have kept instructor's remuneration low. As the same situation does not exist in the helocopter industry, helicopter PPL QFI's get a very much better living, but then of course, helicopters cost much more to operate.
So now, everything is turning full circle. The powers that be have given up trying to get fixed wing instructors a decent standard of living and as PPL instructors did and can do the job perfectly adequately are seriously considering removing the CPL requirement to the holding of an instructor's rating.
P.P.