How much devs make on patreon is mostly down to luck. a lot of good games have fewer patrons that viit does.
his patron numbers have also been consistently trending up for a year, so the story changing didn't negatively impact anything. most of that negativity is just a group of posters here who didn't support him to begin with.
I think saying success it's mostly down to luck is insulting to some of the devs that work hard and make bank from their projects. It's true that once you reach a certain level it gets easier to sustain and grow your fan base, but getting there is the hard part. Haley's Story has been a great visual novel since day 1. I didn't like the twist and cancelled my pledge a couple of updates ago, but the game is still well above average, so it's not surprising it continues to grow it's earnings. It's also worth of note that Viitgames has the lowest membership level at 5 dollars, so that too helps bump the monthly earnings compared to other similar game, who usually start at 1 USD.
Also, posters on f95 tend have an impact, because for most of these titles it's the only place that has regular discussions going on about them, that are not the usual echo chamber dedicated discord channels tend to become over time. Not to mention the word of mouth can bring in a lot more future patrons than any product promotion. I guess having a top rated game on the biggest adult game forum, even if it's pirated content, can't hurt.