I think that is correct. You are not going to make $1MM as a senior manager of social media marketing. The only way to get to $1MM is to get into the executive ranks.
And even that is not enough! There are lots of executives that are not making $1MM/year... You need to be positioned as an executive that is uniquely placed to drive the business. And THAT is only possible in some types of roles.
"Traditional" here refers to employment by a company (rather than self employment or starting your own business). It is not "traditional" in the sense of "an average person off the street can make $1MM/year is they follow The Secret"