Even with assets in place his update speed is way too slow to justify two games at once. The 0.02 release of A.D. took 4 months and the upcoming release of F.I.L.F has been in development for 3.5 months with another couple of weeks likely before we see it. His previous releases were taking about 4 months on average, too, so that means his rough release timeline moving forward will be delivering two updates on a game then taking a full year (8 months to develop two updates on the other game + 4 months to develop the return update) before you see any story continuation. Unless you're a fan of both games and perfectly fine leaving one to linger for a year at a time it's hard to justify staying on as a consistent patron, and that's very bad for business.
I'm not wild about your math.
It doesn't matter how long it is between updates. The key factor is how many hours of content per month of development.
The rough average is around 30min per month. NLT is on the high end doing a full hour a month but he's a monster.
If it takes four months for an update to release, so long as there is two hours of content in the update, then there isn't a problem.
I've posted this a few times but this is a common issue for F95 users. If the updates are big but have long release cycles users complain that the updates take to long. For example Waifu Academy's last update took almost 8 months to come out but it had six hours of content in it (so over the 30min a month average).
Midnight Paradise is normally on a monthly release and has pretty consistently been about 30min of content in it. Users then complain there isn't enough content in the release.
All that said I do agree that doing two games a month is never a good sign.