Cruz hasn't "discovered" anything. Everyone already knew that. The issue is that you don't have even 50 GOP Senators willing to go along with it.
I'm not sure why so many people seem fixated on the 60 vote threshold when the reality is that we don't even have 50 Senators who agree on what should be done. And if Cruz (whom I do like) really wants to call someone out, then how about calling out his fellow Senators, by name, who are resisting? The problem isn't McConnell -- it's the wayward Senators who won't let him get to 50 votes. But it's more popular to go after the leadership rather than to call out the individual Senators causing the underlying problem, so that's what everyone does.
I'm not a fan of McConnell, but he's not the real problem here.
I agree that "50" may turn out to be the problem. Collins, McCain, Murkowsi, Graham probably a few others.
Those are the most powerful people in America, now. Like it or not.