IME, it has usually stemmed from "that's how everyone else is doing it, so we should too" without considering specific use/business cases. Senior management were simply not willing to deviate from the norm.
Do I care if they pay my salary and the tools are usable?
It's just not what the GP is describing. In some orgs you end up with these expensive, standard-ish "suites" that are way too generalized, don't solve business needs as efficiently as other tools, are painful for ICs to use to meet requirements, and it seems like no one can really explain why these tools are being used over something else other than rumors (the previous CTO came from this vendor, we got a sweetheart deal 10 billing cycles ago, etc.).
So really this an issue of ownership; someone needs to be accountable for infrastructure decisions and outcomes, and it's way healthier for an org if ICs are aligned with management on the same. It sounds like you're not in that sort of org, so good for you.