I can think of a couple other examples in music but it’s certainly rarer than in games. Dr. Dre’s Detox (about 14 years before being canceled, though supposedly he’s working on it again) and Chinese Democracy by Guns N’ Roses (about 10 years).
It seems like indie devs have a bad habit of biting off more than they can chew. However as you say they are so earnest that I don’t mind so much following their development hell. I’ve been casually following Routine since it’s first trailer. I’m normally too much of a baby for horror games but I just love the retro-future aesthetic. I also followed Stardew Valley for most of it’s lengthy development time as it underwent massive changes to both gameplay and graphics (the dev was learning pixel art as he went). I’m kind of amazed that it not only turned out so well but went on to become a surprise big hit.