>Any examples, at scale, where communism didn't degenerate to authoritarianism?

I'm usually hesitant to back up historical instances, and I'd rather be pushing for new investigation into to methods that 21st century Marxists and Communists and anarchists in general can use to advance their cause. Of particular interest is Bookchin's "Communalism" and the writing of Slavoj Zizek, further Paul W. Cockshott's ideas of computerised central economic planning.

Orwell wrote fondly of revolutionary Catalonia.

>When you keep the centralized structure of the state, you're perpetually at risk of groups hijacking it.

This is unfortunately true. Back in Marx's time, there was some debate between the Marxists and the anarchists at the International Workingmens congresses. The anarchists wanted to do away with the state immediately, but Marx and Engels posited that this would be actively harmful - because once the workers seize control, they must secure their newfound power to suppress counterrevolutionary activities by the powers of old - the bourgeoisie.

>The lower classes get screwed either way, but at least in a capitalist democracy they evidently (given the past 200+ years of political history) are more capable of extracting concessions through shifting alliances.

The capitalist democracy has done little to reverse the enclosure of the commons in Western Europe, rights such as shorter working days, the end of child labour etc. had to be fought for by Socialist parties of the day. Although I disagree with the premise that capitalist democracy is a good way of acheiving the aims of the Socialists, some would disagree with me - Oscar Wilde and Bernard Shaw are examples. My core reason for distrust of the bourgeois democracy is that I view its purpose as protecting the flow of capital, the people in power are rather powerless when capital rules.

>Regarding socialism, is there any correct definition?

There are a variety, though I tend to side with what the "Socialist" philosophers and political economists of the 19th and 20th centuries have written in favour of, generally, the democratic ownership of the means of production, in tandem with the abolition of private property and the class system. We must remember Marx here:

"Communism is for us not a state of affairs which is to be established, an ideal to which reality [will] have to adjust itself. We call communism the real movement which abolishes the present state of things. The conditions of this movement result from the premises now in existence."

>Indeed, hasn't almost every self-described socialist government in the world almost entirely divested itself of legal ownership of the means of production over the past 40 years?

Here's the thing - the abolition of private property and its functions is about no ownership, not everyone owns.

I must say I disagree with your point that we need to move beoynd ideals and into manifestations. Marx said that the job of philosophers hitherto him has been to describe the world, and that the point is to change it. To be reducing the goals which have been clear to those goals which are more severely restricted I think is a bad decision. To redefine Socialism as a policy which fits within capitalism is to miss what Socialism has been about since its very foundation - radical change and the removal of class systems. If Socialism were to change its meaning, what word would we have left? Communism? In Marx's day, these were synonymous to my knowledge. In Lenin's time, they had changed. Do they need further changing? Other than to appropriate the word to turn it into something it is not, perhaps even with nefarious intentions of luring over dissatisfied people and saying to them "This is the Socialism your friends have talked about" so as to trick them, I think not.

I insist on stopping the changing definitions, the sly replacements - for when concepts are removed from the lexicon, there's little elsewhere for them to go. Gone will be the Socialism Orwell talked about, and replaced with it will be the one Keynes never called as such!