By something else, I didn't mean Communism. I meant "it depends".
Mostly I responded because "What is the alternative?" implies to me a choice between Capitalism and Whatever Else. That would require more control over the situation than we actually have. At some point, Capitalism will stop being a viable process, be it for ecological reasons, cultural change, financial crisis, whatever.
I'm not saying that we don't have agency, just that choosing Capitalism from now until forever isn't really within our practical sphere of choice. If no other set of relations is viable, human history will get really bleak really fast.