The issue is not that the FSF failed, more that most people simply don't care enough. Similar to privacy, which in the end leads to revelations like Snowden's leaks or the Equifax data breach to be effectively shrugged off by most. Not because it's unimportant, but because in the real world it's very low on the average person's worries. Many non-tech people still struggle with sending emails or telling the difference between SMS and WhatsApp messages; issues that Stallman talks about are simply not relatable for many despite their relevance.
Which, in my opinion, makes the further development of FLOSS(or however you want to call it) software only more important. So that the typical user has a point of comparison and knows what can and should be expected from software products. That weird bugs, intransparent behaviour and dark patterns are not supposed to be the norm.