Let's be real, Hyao is sort like Paragon in the space, very few indie porn game dev I know has the diligence Hyao has.
- He's well respected by his peers, he's good at networking, I heard he's also very helpful to other devs
- When encounter hardships (Like when ZoroJ left), he actively trying to work things out
- He's very pro-audience, he's monetisation is very fair, no pay-walled exclusives, heck he even put in-game cheats for free which almost all other devs charge high tier money for
- Not to mention the degree of productivity like you said
- I also can't recall him complain about his personal life nor accident that require him to stop
The fact is, neither "Playing FFXIV" nor "Need a break cuz IRL (So many times)" are reasons to not work on your project, They are just excuses, indicated your heart is not in it.
The speed of After Class is that of a Hobbyist doing something as a hobby and others support (financially) cuz they like what his doing, NOT a professional who charge monthly for the product.