I'm an artist and a programmer, the kind of 'creative' you are talking about, and see myself mirrored almost exactly in the original post. There are many things I care so much about I 'will likely always be motivated by them'. I am in love with all of these.
The problem is that same motivation likes to vanish for weeks, months, years at a time. I have no control over this. That's what ADHD does. That's why it's a disorder, not just misunderstood creativity. We ghost on our own dreams, inarticulately.
I already consider myself "blessed" to know what I like. I would just really like to be able to like it for more than one maniacal sprint at a time.
A solution to the problem of our clumsily entering and exiting a role (above the level of temp work, turking, etc) would be nice - in no small part because it seems like this would help people without ADHD too and, therefore, scale. I've been looking for a solution to this for most of my adult life. The only remotely consistent one I've found is 'long tail' type things - things one makes once and doesn't have to think about, like resources (books, writing, references), assets ('crafts', reusable design, etc).
That isn't enough to build a career off unless you get astronomically lucky - or come upon the necessary resources to delegate the less ADHD-friendly parts of this kind of business - promotion etc - to someone else.