The 8th part of Questionnaire ("When did you discover Touhou?") is really surprising. If the statistic is true (most of the participants answered honestly), a big percent of fans who knew about Touhou since PC-98 remained, but most of the fans from the Golden Age (PCB-UFO) didn't participate in voting. Did they move to other fandoms? But still characters and soundtracks from EoSD-SA are most highly ranked, Most of voters discovered Touhou in the period from 2015 to 2020. So it might explain, why for several years in each voting around one third of participants had not voted before (this year again). But it can't explain some strange results from previous years.
There are some other interesting moments. Around half of the fans have not played most of the mainline games. In "Touhou original game competitions" (question 11) there are UDoALG (the latest "Phantasmagoria" (which is not a "Phantasmagoria")) and Soku, but no AoCF. More than one third of participants discovered Touhou via Youtube, so it maybe the best instrument for popularization. Less than half of the fans likes Touhou Fandom (IMO, it is a problem), even Touhou games are more loved.