Has real socialism ever been tried?

Socialists claim that previous versions of socialism went wrong because of external constraints, or because it happened in the wrong place, or because the wrong people took over, and so on.

Fair enough.

Let’s do a thought experiment, then, in which we just assume all those factors away. Let’s do a thought experiment of a socialism led by genuine idealists, and under idealized conditions.

And let’s see how that turns out.