Art is not what bottlenecks this game progress. I bet illustrations for tribe update, or whatever it's called, were done months and months ago. And even when SC was actually getting updates, Kain had time to make a shit-ton of art for that Eden Crest game of all things. Hell, I think there's still more sex scenes in Eden then in main one. Not to mention that lack of art (which there is none) have absolutely no impact on being able to create and produce the rest of the game. The reason he trickles this redesigns out is to show something, anything at all to keep milking Patreon for as long as he can without doing work himself.
That said, I like Devil-V's work and, apparently contrary to popular opinion here, find it much more appealing than Kain's. Wish it wasn't wasted on keeping this scam alive.