“But others say it is foundational material”
CISSP requires 5 years of industry experience. Clearly not foundational. I pin it as intermediate. The EU agreed, ranking it equivalent to a masters degree.
https://www.isc2.org/News-and-Events/Press-Room/Posts/2020/0...
It's definitely true to say it is framed as foundational in some quarters, however. Consider the common "CISSP required" "entry level" roles that are regularly shared and pilloried
Calling it equivalent to a masters was also a marketing coup, there was plenty of discussion and pushback on that characterization when it was announced
