games always contain hand-drawn art, this is always a bottleneck in game development, as you always have to wait for the artist to finish the work to release new updates
So it doesn't matter how many games he makes at the same time, as the development and waiting time will be the same.
Maybe they should stop adding new characters and side content to prolong the development instead of just, you know? Finishing the game(s)? If they stop adding extra workload for the artist by the unnecessary side content and the "seasonal special" BS, the games would be finished, or at least close to being one by now.
He already finish / completed 3 games out of 6
By 3 of the games you described are finished, they're more or less just on the technical side. The game was completed abruptly with a very unsatisfying finale; Almost like it got axed just because author got bored and just wanted to focus on their new game(s).
Now they got a new favorite child, their other ongoing games are going to end abruptly like their other games. Rinse and repeat.
Every single of their games gave the illusion of being bigger and longer than it supposed to, because they keep halting the main story in favor of some random side content and seasonal updates. I stopped caring about Zombies Retreat 2, but last I heard they added like 3 new side characters for some reason that barely have anything to do with the progression of the game, while the character that has been introduced from the start, like the main promotional point of the game, have yet to be utilized properly.
80% WEG that got big always do this exact same shit. Updates are literal nothing-burger of some side characters that won the patreon poll, instead of progressing the main story and scenes associated with the main characters, just so they can prolong the development by blueballing and tease the players for the "main content" so people would keep waiting and "donating."
Creating a new game just so you can tell your patreon that "I'm working hard on my new game right now so I can only work very little with my older games." is one of the usual patreon slow drip scheme. Alongside the "I'll remake the game from scratch because my artist quit on me" and the "Sorry I can only add 5 minutes of content this month, but here's a new scene with a new character that nobody knows about."
House chores has been in development for 4 years. And they're still on version 0.15. Assuming that they understand to use version naming properly, it's only 15% of the game completed. That's 4 WHOLE YEARS for only less than 1/5 of the game completed. And you think artist is the one to blame?
I can't blame a man for trying to make bread, but if it becomes your main goal and you went all sellout on your original passion and original goal, then sorry, because I'm not a fan of author who do shit like this.