The paid artbooks AREN'T ON THE MARKET ANYMORE. The smut stuff is ALREADY AVAILABLE FOR FREE.
If I'm looking for smut, I'm not going to be starting off with a bunch of patreon blog links to read through, post by post. I'd have no way to discover new stuff, or to search for things I want to see. I'm limited to whatever the artist posts on their blog.
SadPanda posts galleries that are tagged. That means I discover new things.
Artists either draw as a hobby, or get paid commission when they draw a new picture. A new picture which then serves as advertisements for further services. That's their fair share. Paid to draw.
Your described system presupposes perfect, innate knowledge of everything on offer before I reach for my wallet. That's not how things work, and that's not how things will ever work.
Archival, organization, and discoverability are the rules of the game. There's already a practically infinite amount of high quality content available for free online, especially pictures. They're fucking everywhere, in the thousands. We're on a god-damned IMAGEBOARD WEBSITE you newfag. Once you stick around for a few weeks, you'll start to see that images aren't worth anything. They're a medium for communication first and foremost. If someone threatens to not make any more drawings of naked people unless they get paid, then there's a thousand other anonymous people who'll take their place instantly.