Wow, dang. I mean, it's a stretch to say that most don't work out. By saying that, you're assuming that at least 51% of the ones posted here are duds, which might be the case since most of us are broke. Money is a big motivator in most cases.
While I agree with your point about teaching ourselves how to draw. However, it is extremely hard, and not everyone has the talent or money to make their own art or use AI art. Take it from the guy who's been kicking the wall for the past month, learning how to draw.
Old drawing:
New one:
However, I don't think that we should throw away Collabs and rely on ourselves. The ecosystem might be trash, but writers might also be the ones making it like that. I think that we might be going about Collabs the wrong way.
Essentially, most of us value our work highly. I agree with that, most of us have our own stories, and it's like a kid to us. However, we have to realize that others feel the same about their own works.
If you are a writer, but you don't have any money and want your work made into a comic, there are many ways that it could happen. However, posting a Collab that essentially says "my work is great, feel honored to draw it" then no work is put into it and it has a small amount of subs or following is not a way.
There are 3 clear ways and a fourth maybe.
The best way to get an investment is to have a clear plan. Write a summary, the plots, the arcs, the different characters, the setting and explain every aspect of your story. Also, sketch out your scenes and make a draft of your comic so that artists need to do the minimum amount of work, cause if you love your work that much, you should put into the effort.
And for the point that people always love to bring up about their work being stolen: It doesn't matter if you think that someone's gonna steal it, cause, for the same reasons artist won't draw your work, your work is more likely to succeed than get stolen, as nothing is proven, and thieves don't steal gems that look like rocks on the outside.
However, by posting your full work, you open up so many opportunities, and the benefit outweighs the cost by far.
1) you seem more professional and dedicated to your work
2) you're more likely to get artists interested in your work as they know every aspect of your story and only have to put in the minimal effort to just draw out your plans
3) you could get a sponsor who's interested and gives you support
4) people love quick wins
Essentially, love your work to death