Motivation depends on so many things. And you need to understand that there are two very distinct types of motivation and they couldn't be more different from one another:
- extrinsic motivation - this type of motivation is fueled by outside factors; think getting a job you don't like because you need money to pay the bills, and the only reason you'd put more effort in is if you were paid more; otherwise, there is no real motivating factor
- intrinsic motivation - this one is strongly linked to what you actually want to do as an individual; it may take years to figure out, but more often than not it's linked to either than one creative activity you could do for hours on end or something that you can do so naturally and easy it seems it was meant for you (videogames don't count sadly unless you want to go pro)
Intrinsic motivation comes from within and it's very powerful. And I always found it funny that this motivation is strongly linked to that one activity you want to do, but told not to because "it's not a real job".
What I want to say with this long, intertwined post is that, should you want to be the best guitarist/musician in the world and you are at peace with yourself (i.e. you know that this is who you want to be and you are no longer ashamed to admit it) and with people around you being judgmental pricks because "muh society values", motivation will come.
This all worked for me and people are very different, but some things just don't change between us.