100% agree with all of the above.
I worked for a major aerospace systems company and had a company Master Card (and used it plenty).
McMaster-Carr would not give me a discrete customer number because my shipping street address was the same as the company's.
No discrete customer number meant they couldn't identify my specific spending so they would not send ME a catalog. McMaster told me "We just sent a half a pallet of catalogs there within the last month". None of those catalogs got to my desk in an engineering department. I bet very few got to buyers in procurement. I also bet that most of them went into a dumpster (or maybe sold on eBay). It was extremely frustrating.
On a lighter note, for some time in the '90s, McMaster ran a forum on their site. People would ask questions and the community would reply, but more importantly, a McMaster person would reply with a suggestion that Part Number 9XXXXAXXX would solve the problem. There was a sub-forum where the catalog was the main subject, IIRC. Anyway, I read replies there for hours and laughed, ROTF. It was the funniest few hours in my life. It was liberating to read that so many others were equivalently frustrated by the McMaster catalog distribution policies. The expressions of the frustration covered the spectrum from calm, specific, rational to ranting rage and questioning peoples characters.
I don't know when the forum evaporated, but it did.
AFAIK, McMaster does everything else in a world class manor. The catalog distribution . . . not so much. Their policy seems, to me, to based on a doctrine developed in the 19th century. It's incredible to me that they won't even sell the catalog.