It was not phrased as a guess though, but as a "fact" that cannot be proven

Also most human communication isn't about formal logical reasoning. It's only a fallacy when applied in the form "A therefore B". We can make all sorts of useful and relevant observations about human and societal behavior that aren't logically rigorous.

Yes they can, but claiming a theoretical future event as fact (or inevitable) I would consider particularly fallacious as it's impossible to prove.

And I think history also shows these claims rarely end up happening the way these alarmists think it will.

Usually when a slope appears, regulation steps in, technology evolves, or the culture shifts, rather than society devolving into some inescapable dystopian hellscape.