No, it isn't. The collapse of capitalism is the inevitability. This idea that communism is inevitable is kinda counterproductive as it makes it really easy to infer that you don't have to do anything in order for communism to win.

Not that we should stop saying it, of course. I just think we should be more mindful of our context. We should be saying it as comfort and encouragement to those who are losing hope, not to rally others to our cause or to intimidate our adversaries.