This is interesting timing. I was asked at work to remove our RSS feed. Turns out no one but me knew what it was for they just saw the link in the site footer clicked it their browser showed a bunch of xml and they thought it was broken. I checked the logs turns out it gets 1000s of requests a day so I think that convinced them to keep it.
Some RSS readers are quite aggressive with their polling time. At the same time, a single request may serve thousands of users. However, you can check your logs and get the actual number of subscribers, at least for popular RSS readers: https://darekkay.com/blog/rss-subscriber-count/