Eh, to be fair - Sel is a pretty good writer in AVN/Smut category. He's a fairly decent one even outside the scope of porn.
His biggest flaw right now - is the lack of planning. I've been writing a lot of stuff for the past 5 years, both fiction and non-fiction, and I've realized that if you don't plan your shit - it's gonna be all over the place. Characters will become inconsistent, story will branch and develop its own sub-narratives, the main plot is gonna be lost somewhere in a ditch. Everything's gonna get messy unless you stick to at least some sort of plan.
And honestly - the fact that most characters stayed mostly consistent throughout 5-6 years of writing on a whim - that is a fucking impressive feat.
So yeah, he's a narcissist and a very egotistical fella, but he's a decent writer.
I think ultimately it will be decided by how the story ends. Take GoT for example - great story, shittiest ending, nobody rewatches it, despite very very good first 80% of the show. Couple of years ago found a story that got me hooked for like 2 months of non-stop reading - but the author just doesn't know when to stop and keeps going and going and going and adding more to the harem and going and adding... And judging by the comments, he's been doing that for 8 years with no end in sight.
IMO - end of the story is an extremely important part and the writer's ability can't be judged until the story ends.