It wasn't that long ago, maybe midsummer of 2008, that only the bravest of the providers actually participated in voicing opinions and comments in threads on this board lest they provoke nasty comments from the many rude bullies this board was riddled with. Since then, the tone of this board has mellowed and matured. Partly, due to the change in management at the top, but also due to adherence to the posting rules of respect and decorum on the part of the moderator. I think, too, that a lot of it is due to the tone that many of us hobbyist posters set to make the providers feel comfortable enough to post. Yes, you can call me a White Knight because I have no problem coming to the defense of a provider who's not being treated fairly and respectfully. (Henceforth, when addressing me please lower your eyes, bow your head and address me as Sir Drumsticks, thank you.)
Of the seven provider top 10 posters you refer to, three of them never or seldomly participate in theme days. So that works against your argument. There used to be more hobbyist posters in the top 10 but, because of the recent LE events, several (many actually) of them have taken a noticeably lower profile and don't post as frequently. This will likely change as the dust settles. That also works against your argument.
Theme days are not new to this board. They've been going on ever since I've been following the MN board and other boards. With the demise of MFP, theme days have been more frequent as the providers migrate over to TER. At MFP we used to have frequent theme days or theme posts and everyone was cool with it and enjoyed themselves.
Anyway, some sage advice:
One who proposes a hypothesis and supports it with dubious and/or controvertible evidence is called 'a fool'.