Would you have said the same about slavery? "simply a tool"?
You would "choose the system you have to work with" and just say "it is what it is"?
Not that you get to choose anyway!
Describing the ongoing evils of #capitalism is not "lamenting on past mistakes". Capitalism is enforced by violence and coercion NOW, TODAY. #Enclosure and #colonialism are processes that continue EVERY DAY.
Capitalism is like cancer. You can't tame it; it serves no healthy useful purpose. It is a parasite on humanity and must be eliminated.
If by "Democracies" you mean nation-states, no, I have no state-based solutions to offer, nor are any state really "democracies". States are part of the problem.
I think communism does describe the solution but I suspect you have an authoritarian state in mind when you use that word and I most certainly do not mean it that way.