The Steam subreddit has suddenly become all about actual steam and steam trains

That's hot.

They probably could have gone the NSFW route too and made it a sub for steamy pictures.

I wonder what all these other companies think of this, who had spontaneous unofficial communities spring up on Reddit, only to have them all turn to shit over the course of a few weeks.

I use Google Fi, their customer support is atrocious but they have an employee who moderates their subreddit and they even have a Reddit request form to get cases escalated. I don't feel like I can ever delete my account because I'm screwed if I need Google Fi support without it.