The root cause of "such behaviour" is that the Patreon system is a scam. A subscriber-based payment system that, using legal sleight-of-hand, pretends to be a patronage system. So, content creators are incentivized to give some content monthly even in itty-bitty amounts.
The Devs of AVNs can pretend that non-canon wallpapers are somehow worthy of what a "patron" pays monthly.
You aren't wrong. Patreon rewards the dev model of good first couple of updates, and then for the dev to drag it out as long as possible. The absolute worst thing to happen for a dev is to finish their game. Then all the income stops. So devs have little incentive to ever finish. I applaud the few like DanielsK, Caribdis, and Mr. Dots, who release consistently, finish their games, and then immediately start the next one.
If you were a dev that were trying to maximize your revenue and minimize labor, you basically finish your work at your own pace, and then hold on to each release, writing fake status updates every 2 weeks or so and releasing the occasional screen shot or wallpaper to keep interest up, until you lose a certain percentage of subscribers, say 30%, whether that takes 6 months or 1 and a half years, and then release and repeat.
I consider Radiant the penultimate case of this dev style. Lots of build up at first, a reasonable time frame for first update, then very small yearly updates to keep the Patreon cash flowing with very little monthly effort by the dev team. Lots of popular games here, too many to count, do this exact same thing. Releasing regularly, respecting your fans, is really the exception rather than the rule.
But, we all have to remember that without the Patreon model, there would be almost no adult games. How many adult games were there before Patron became popular? Very, very, few. There were some Japanese imports of mostly anime style, a small handful of Steam games like House Party once Steam allowed adult games around 4 or 5 years ago, lots of low quality flash games not worth playing, a few expensive low quality monthly subscription games or those where the base game is free and you buy assets for an exorbitant price, and that is it.
Nothing with any type of interesting story, nothing with high quality realistic renders at all, because it isn't worth a devs time to spend many months of labor and rendering time, buying assets and electricity for your power hungry rendering PC, writing and working for free, just to release something a year or two later once everything is complete for $10 or $20 per download, just to get eclipsed by the next big thing and forgotten a few months later. It is a lose-lose proposition, which is why practically no devs charge only after their games are completed.
Patreon, as much as some devs abuse their fans goodwill (and forgetfulness to unsubscribe, people are still subscribed to Milfy City for example), the ability to slowly develop your adult game in your spare time, and get a few hundred or more a month to make it worth your while, keep the games coming.
Whatever your favorite game is here, it wouldn't exist without Patron or a similar fan-based monthly paying model. Radiant certainly wouldn't exist.
