I kinda disagree with you as someone who's just a writer. It's a skill based thing. If your writing's good enough the oppurtunities will present themselves! This isn't any different for art or music or anything.. the skill and the progress of said skill are what people are looking at.
You can find writers everywhere, sure, but how many of those do you find that are able to craft a well-executed story and narrative? Similarly, you know the amount of artists out here? Yeah, I'm sure people get picky about them too when it comes to this. People want artists that can depict complex action scenes and draw all these perspective shots, but how many of them can pull it off?
What's attracting them to the experienced writer and equally experienced artist is the level of where they're at, and it's not like either of these is a god given talent! You can work hard from the beginning to catch up to them! Anyone can if they put their heart and soul into it! The crazy thing about people in the creative field is that they have an outstanding amount of relative failure and constant redoing, but people tend only look at the surface and assume that they just started there out of nowhere!
I know your intent wasn't to be dismissive, but it doesn't sound like there's a proper amount of respect either. You just wanted to remark on the whole idea of "you guys can actually make the vision you're seeing your head and that's awesome because I can't do that!" ..and that's fine! I completely get that! But here's the thing, you can always start learning, and become just like these people. You have the ability and the choice to narrow the gap, if you want!