you do realise that the 0.17 update was a rework right? meaning the patch was mostly a rework of existing content, not new content.... you should read the update.
It was a complete rework of aunts scenes and images, and a bunch of other characters with their new rig system, and a partial rework of certain scenes with the mom and sister.
To exaplian rework meaning: redrawing old scenes, new base models (aparently they are doing this rig thing now, which is good long term cause it means faster updates), improved story etc. so of course this is little to no new scenes as it was the old scenes that had all the work done on them lol XD you might want to actually learn what has been changed before you go making baseless accusations.
Also one big difference between the two, dual family is not free, summertimesaga is free and always has been free, people who give money to that are giving money cause they want to help the devs not because they want access to the game.