The competitive nature of the scheme with many high quality candidates means that many people who have very good qualifications and experience are not going to get through.
And academic qualifications are not the be all and end all, they certainly help and they will get your foot in the door, you have to open the rest yourself using other skills you have.
Its just the way it is as there are only a limited number of spaces so not everyone can get through, even if they are likely to be suitable for the position.