This depends on site audience and content strategy.
In general, subscribtion-alike processes had moved to social networks nowadays. An amount of RSS and even email subscribers is rather small comparing to Instagram, Twitter, Youtube etc. Younger audience doesn’t use RSS. So this communication channel is decreasing from year to year and to my opinion has a very small chance to rise again in future.
On the other hand, supporting any technology or channel has costs. Writing posts or newsletters is not always profitable comparing to other ways of communication. We can spend an hour preparing a text, but we also can spend it creating a bright Instagram story, for exmple. And as we always deal with limited resources, we have to choose channels with best ROI and focus on them. It’s much more profitble to strengthen points that are already strong rather than carrying the weak ones by inertia. Although it may seem irrational sometimes until you check the results.
I don’t mean RSS is totally useless. Perhups it’s still a good channel for media, blogging or some types of eCommerce. And plenty of people still love it.
But most of my sites really don’t need RSS functionality as they have no internal blogs and the amount of direct subscribers is 10-100 times smaller than on Instagram account. Keeping RSS (or any other unused piece of code) enabled is excessive as I have no extra human resources to monitor related security issues, possible content duplication, accessability, legacy and other technical aspects. It’s much simplier to disable it and focus on something important.
P.S. Certainly, it’s just an IMHO. I understand that there are other ways and situations and respect any private experience.