J. Kavanaugh was the tipping point. Conservatives now enjoy a slim majority. When Justice RBG goes to the big reeducation camp in the sky, there will be a slightly fatter majority. With any luck Souter and Roberts will be getting longer in the tooth soon, too. And so on and so forth. All Trump needs to do is win one more POTUS election, and help the Republicans win one more mid-term after that, and SCOTUS will be that much better.
You are correct, of course, and every leftist on the globe, especially those within our country, will work to defeat that possibility.
I am an optimist, but being a certified risk-taker try to keep my head on a 360 lookout for threats.