have there been any writings, surveys, or studies
If this is your core question, I suggest putting it somewhere up top; people will get halfway through your post, find something they want to respond to, and just respond without realizing you're not looking for anecdata.
But no, there's nothing like that as far as I know. And I feel this sort of thing would get a lot of play from ex-redditors, so I agree with the other guy that recent shifts would have been too recent to have been analyzed.
(As far as anecdata goes, I've always found subs that focused on a location instead of a topic had a more prominent conservative presence, as location subs bring out a lot more fierce rhetoric as people feel they're defending their homes from perceived threats.)
Guessing you didn't see the recent news about Epic doing a big layoff and shedding properties recently?