Again every update gives a litle content

How about focusing sisters or milf mother <---- they should have priority to get fucked first
Yes but... If you finish the content for the "family" first, then afterwards you will lose supporters. Because if you make an IC game, obviously the supporter donates until he has IC content. (the majority of them)
My own experience with summertime saga, (not the best example I know) the mom sis and aunt paths were finished a long time ago, and devs do not bother, to add new content for them in the future... I'm not saying its always like this, but most of the times... Therefore the devs are stretching the family content as long as they can... Because in 90% that is what makes the profit...
It depends on the focus of the game, if it is family-focused, then it takes ages to bang your mother

That's why I wait and keep asking players if there is any mom content

Because I don't give a sheet about side chars, I'm literally skipping the text for them...
And I'm sure if he wouldn't have only 142 patreons, the content would be satisfying.
This is only my opinion...