I write on my blog, but I am not sure who I am writing for. Which is fine, because in the end I write for myself. Years ago you would get comments, posts would get linked (remember pingbacks?). Maybe as time progressed I started writing more niche things that reach nobody, or maybe that web started disintegrating. Hope it comes back, but I will not hold my breath. I will keep posting though.
Some people have been following my blog for over 10 years. The only reason I know is because someone decided to email me on a random Tuesday. You'd be surprised what you find when you look through your logs.
Some of the major hosted feed readers (Inoreader, Feedly, Feedbin) include subscriber count in their user agent. I usually run a filter on requests to the feed links in my access logs to get an idea of how they're changing. Anecdotally, my subcriber count reaches into triple digits with only those counts, but I've never gotten email from readers and generally only get feedback promoting new posts on socials. The counts are about as nebulous as follower counts, which is to say most people probably subscribe/follow and forget.