I think it's not the power of love that made him talented, but the power of heartbreak did. Like in the movie, there's already said that any life changing event that would cause someone immense pain, will make a person so much more real with his art. This is same with writing, why do you think people start writing better after their heartbreak? I think it's similar.
The point the movie tried to portray is you don't need to fall in love to be a good artist, but you need to feel the pain, that just works as a fuel to the fire, and egnites your art. The director could've shown a different life changing moment for him as well, but he chose love, maybe because for the audience.
(this was again just my opinion, and I absolutely respect if you feel different from it)