I am using this as an example and to see what people have to say about this and what this specific individual should do in a situation like this.
If there is someone who only enjoys coming up with musical ideas (in this case, songs in his/her head), but enjoys nothing else in life (learning and actually physically making music) as well as other things in life and only enjoys expressing his/her own ideas.
This person has gained vast knowledge from listening to music, and based off that knowledge, has produced songs in his/her head (songs that are, in fact, to be the next best songs in a movie or somewhere else). Without knowledge, this person would not be able to create any song in his/her head. So this is where this knowledge would come from (from listening to other music). It is obviously knowledge that can't be used in physically making music and the person does not know what that knowledge actually is (again, it is a type of knowledge that only the person's mind alone uses in making music--the person does not know how his/her mind is creating music, but when he/she focuses in creating a great song, it will happen).
This person has created these powerful songs in his/her dreams (as well as other great songs in his/her head in the waking world). Now this person has a goal--which is to perfect these songs into the real world so that they will be known by others, but has no musical experience and has it in his/her head that he/she wishes to learn and physically make music, but however, when he/she goes and does it, he/she does not enjoy it at all. Also, when you are first learning to make music, you cannot create your music at this point (so the idea of creating your music is shoved off into the distant future and all that's left now is just the physical aspect of making music alone in order to experiment and learn more, and of course, to just have fun which doesn't exist for this person). As a result, since this person only enjoys making his/her own music, he/she would give up because there is no enjoyable aspect in learning and physically making music alone for him/her and because he/she can't make his/her music at this point. If his/her songs can't be perfected right now, then there's no point since there is no enjoyment for him/her. If this person wishes to physically perfect his/her music, then unfortunately, this would have to be a lifestyle that the person is unable to live, and making music in his/her head and physically learning and such are two completely separate worlds for him/her and he/she is unable to make those two worlds as one.
But what's the use of having such a mental talent that you are not allowed to physically pursue (due to your inability to enjoy other things in life and that you only enjoy making music in your head and just expressing your ideas alone and nothing more)? This person would be a musician (a composer who only composes music in his/her head--but that's it. This person is not a composer physically). I mean, I bet many people would say that this person is no musician and has no talent. But again, this talent is something special and different (something that others do not recognize) as it doesn't exist in the real world and exists within this person. This person clearly has a natural mental talent to have created such powerful songs in his/her head, but has no natural talent or desire for physically making music. He/she truly enjoys and feels very deep in creating songs in his/her head, but there is nothing for him/her physically. So what should this person do if he/she wishes to physically perfect his/her songs into the real world so that they will be known by others?
If you only do something (in this case, learning and physically making music) not because you enjoy doing it, but only because of the songs themselves/their power and your goal of getting them into the real world, then there's obviously no point in physically making music. Which brings me back to the question of how one would get his/her songs into the real world if there are no other enjoyable physical aspects in life for him/her.