My experience both working at and with higher end consultancies is that there is no correlation whatsoever between those degrees and any particular consultant’s competency. Some of the best people I’ve worked alongside have been college dropouts and Religion majors.
If you're doing low level design of crypto algorithms, you need to know math. If you're doing appsec reviews or pentests, then a background in software development might help (but is not required).
But there is an entire world of security roles out there that are essential to implementing security that have nothing to do with math or compsci. The security industry right now has a huge problem with gatekeeping, where they think you can't even begin to think about security unless you're already a top-tier principal engineer, and it's led to a huge drought of talent in security roles across the board.
To this day, its hard for me to tell during hiring what makes a good security hire.
I'm going to bet that they did have qualified engineers, because I like to assume the best in people, but I also assume that those engineers may not have been able to make the changes they want to.
In my experience in big companies, corporate bureaucracy and a complete unwillingness to change processes or systems is usually a bigger hinderance to security than the skill level of consultants/engineers.
And they had the nerve to suggest we replace this unencrypted database, which an old legacy system needs entirely open root access to with something secure for an eye watering bill - we don't hire security consultants to replace our legacy systems, we pay them to stop unauthorised people accessing the big pile of data we leave in the open.
Get the gall - they even wanted us to change the interface between our two big legacy systems because it was just a CSV file which contained all our sensitive data on it. Wimps! Especially as we told them they could do anything to make our systems secure, as long as they didn't touch those legacy systems."
Because my degree is in Management Information Systems (MIS), but I've done troubleshooting on both performance problems of the O(n^5) variety and problems of the "not covered in the requirements document" variety... Not sure what else I need to understand, say, memory bounds-checking problems or firewall/ACL configuration problems.
EDIT: expanded acronym
I just say "business and computers and how they go together" when explaining it.
Of course, I never actually got certified because I left the role immediately afterward and never bothered following up. Moreover, I didn't really meet the requirements, which included having some tenure as a security professional. But I'm sure I could have finagled it if I had any interest in working security (I absolutely did not).
Braindump-able IT certs benefit no-one, and expecting people to have MSc degrees in infosec is elitist and very impractical.