I’ll give it my best shot.
A for effort - and I'm not being sarcastic. I need you to understand that before I start pointing out all the problems with this approach of yours.
1936 Catalonia during the Spanish Civil War
Sounds absolutely grand. But how did it fail?
When I ask anarchists this, the answer I inevitably get boils down to something along the lines of, "the anarchists were stabbed in the back by tankies and liberals."
That's not an answer - that's a cop-out.
Firstly, the tankie/lib alliance did not stab the anarchists in the back. They stabbed the anarchists in the chest - in fact, the anarchists saw the knife coming from a mile away and was still incapable of preventing it. It's very easy to blame the liberals and the tankies... it's much harder to analyse why anarchism seems so uniquely incapable of resisting (never mind taking the fight to) the political machinations of liberalism. I'd go even further and argue that anarchism's apparent inadequacy in the face of liberal realpolitik is even more evident today than it was in 1936.
This is not a praxis problem - it's a theory problem. Or rather, a lack of theory problem.
Secondly, studying the successes of anarchist Catalonia (or Makhnovist Ukraine, or the Paris Commune, or whatever failed libertarian socialist project you might want to mention) is a dead-end as far as theory goes. Political theory that is built on past successes are next to useless... theory that is built on a sober (and granular) appreciation of failure is not.
The socialist experiments in Rojava and Chiappas proves this - both owe their existence to tankies who went back to the drawing board, critically reviewed the very Marxist-Leninist fuckups they had committed, and dumped Marxist-Leninist orthodoxy overboard (the fact that tankies dislike talking about these two projects proves as much). Should anarchists, perhaps, do the same? The "lame-duck" status of anarchism since the end of WW2 suggests... yes.
There is, by now, slightly more than an eighty-year gap between anarchist Catalonia and the present time - that's an eighty-year period where anarchists have failed to make any real headway against the post-war liberal consensus. This is not something that is going to be fixed by wishfully hoping that enough people will be "joining in." What stopped people from "joining in" during the sixties? The seventies? The eighties?
My answer to that would be... the same thing that's stopping them from "joining in" now - and that is, the lack of a proper theoretical framework that allows not just anarchists but also the working class to easily problematise the liberal consensus. The lack of this framework is on display literally in the very first source you posted - any self-described "libertarian socialist" that frames the concept of democracy as some kind of "problem" that requires solving will (justifiably) raise a lot of red flags with the working class. It seems that "killing the liberal inside your own head" is something that a lot of anarchists preach... but do not necessarily practice.