Same. I pretty much scan it, anything interesting I open(which isn't a ton). Then, about once every few months, I get tired of seeing 20k unread emails, so delete all unread emails older than x.

Perhaps I'm not a power user, or constant marketing emails have just made me numb to it all.

I basically never receive an email to my personal account that I care about, unless it's a transactional email I just caused to be sent (password reset, email confirmation, shipping notice, that sort of thing) or I'm job-hunting. I go weeks sometimes without opening my personal email. I tried for quite a while to keep the inbox manageable with filters and aggressive application of the "mark as spam" button for anything from a sender I didn't care to ever hear from again, but at some point realized that I damn near never care about an email that I didn't expect to find, usually received within the last few minutes, so there's no point.

Same. My workflow is as follows:

About once a month, I unsubscribe in bulk, and delete in bulk. Other than that, I scan my inbox once every day or two and read anything that seems relevant (maybe a handful of emails per week).