Back like 15 to 20 years ago when I ran or helped manage some hobbyist websites, I added RSS functionality if only because it was "popular" back then.
I can confidently tell you not a single bloody soul used it, at the height of adoption no less.
If I run a website again I definitely won't bother, it's additional maintenance for a feature nobody uses. The cost-to-benefit ratio makes no sense because the benefit is zero.