Yup, in most cases, they are required to solicit and consider input. They are not obligated to accept changes to proposals based on a majority input, or anything else.I remember attending some of the NPRM public hearings in the 80’s concerning major airspace changes (I don’t recall the specific issue, but one of the affected airspaces was the Ontario ONT TRSA). All of these meetings were well attended and some were convention-sized. In every meeting, there was absolutely NO show of support. Speaking out loudly against the change was all of the GA pilots, all of the commercial and professional pilots, all of the related pilot unions and organizations (including AOPA and EAA), airline reps, airport managers and/or owners, individual Air Traffic Controllers, ATC professional organizations, airline representatives, the military, and even some of the regional FAA staff. The proposed rule was adopted and implemented as published.
It is common for federal regulatory agencies to explain why they did or did not revise a proposal based on formal comments. Recall the discussion about the creation of LSA in the final ruling published in the Federal Register. https://www.federalregister.gov/documents/2004/07/27/04-16577/certification-of-aircraft-and-airmen-for-the-operation-of-light-sport-aircraft