If by mastering you mean knowing every single aspect of the language, I don’t think so. I’ll bet anything even Bjarne Stroustrup is nowhere close to that ideal.
There are just so many features in C++, along with the way these features work together, that it is humanly and statistically impossible for anyone to know how those moving parts mesh and work together.
On the other hand, there are many programmers I know who have a high degree of proficiency in this language. The Pareto Principle works here as well: You need to be good at a decently good enough subset from the entire feature set of the language to get most of your work done. The rest you can learn along the way.