A very emotive subject indeed, we all know artists that are great musicians and great vocalists that dont make it, however we all know musicians that are not that good and do make a living at performing and recording.
music for me is subjective so it makes it very difficult to sort it in my head, i dont think their is any right answer , for instance if i had a friend who had no obvious talent but was spending a fortune on equipment and services connected to musical ambitions and was to the detriment of his/her family i would like to think i would say to them.
On the other hand there are artist out there making a living because of their difference as someone already said Ian Brown couldn't hold a note in a bucket however has been hailed as a great indie artist and has made a career out of music
so taking that all into account we never know where it will go.