Most points are valid in this discussion, a student will only be as good as their instruction. The qualities of a good instructor are alot to do with the individuals' characteristics and their ability to relay the subject matter dependent on the students learning styles and aptitude. But without the experience, it can be hard to convey the impact and justification of that teaching aspect.
Many newly qualified pilots would jump at the chance to mentored and supervised to better their skills and abilities, I am one of them, but sadly there are not many such opportunities, and scrimping to achieve FI to gain some employment in the industry is the rung that most can get to first.
Additiojnal courses following qualification would also be great, but a self sponsored individual would rather spend the money on an FI or IR to progress employment, if a CPL pass plus becomes compulsory, are we pricing out people joining the aviation fraternity?