Yes, that's my tumblr allegory! He definitely does not leave his friends better off than he found them. But that can't be the very specific thing that Basil saw documentary evidence of.

Honestly, the Sibyl narrative is fairly banal in the novel. Maybe in the novella it's less dragging. That's the point at which I originally got bored and wandered off. Wilde is so clearly also uninterested in her.