5 or 6 years ago when I was much more heavily using Facebook I would have loved for this to be a thing. I think it would have been a great addition and is something that should be encouraged. Hopefully transitioning more and more away from us being the product and what we are actually using being the product.
However there are 2 big issues with this.
I doubt that Facebook will stop mining us for data and continuing to view us as a product, just now with an additional revenue. For me that was always the bigger of the 2 issues, showing me ads was just the symptom.
The second is how else to they incentivize people to subscribe. Is enough ads enough? Probably not and that is the issue we are seeing with Twitter. Adding in extra features to incentivize subscribing that likely shouldn't be there.