>>19446265Writing series is hard. It requires planning, and commitment, and even then if it goes smoothly on your end as a writer, nothing says some board drama/chuuba incident/just real life won't take the wind out of your sails.
So must people write oneshots. But writing oneshots with structural nuance is very hard. So in order to get good content out quickly, most people prefer to center their oneshots around a single set piece (usually involving a chuuba's vagina and the penetration thereof), rather than around a particular development.