What does it take to be a career writer? Several things come to mind:
A professional mindset
A thick skin
Belief in yourself
The ability to live on practically nothing, an ability that may only be necessary for a brief time but that might be permanent because writers today earn, on average, half of what they earned just 10 years ago due to the many easily available free books.
A tiny bit of ability helps but is not as important as the first 7 things.
A tiny bit of creativity but is not as important as the first 7 things.