That doesn't mean those methods or some form of them can't work, you just assume this is true because you've been given that message by those who need us to believe this for them to maintain power.

And let's say no non-state method can possibly work at our scale, is that to essentially throw up our hands and say, "well, since intelligently shrinking our population and economy to a size that can be sustainably managed and is appropriate sized for our planet (i.e. "degrowth") is unspeakable, and other methods we sorta tried for a bit don't seem to work, we'll just go ahead and continue with this known broken method until it all collapses from overexploitation" ??

Wouldn't it make more sense to say "I want human society to exist in 100 years and for that to happen, we need to learn to live within the bounds of our planet"?