lots of companies are not doing background checks https://www.hrtechnologist.com/articles/recruitment-onboarding/fake-it-until-you-make-it-48-of-hr-professionals-do-not-check-a-candidates-qualifications/
I don't see much excuse for not checking with schools to verify graduation. I don't see much value in personal recommendations as the scummiest characters will always have them.
That was the finding of Rich Douglas' first doctoral dissertation many years ago. He interviewed hundreds of corporate HR people regarding their knowledge and behavior about degrees, real and fake. While some were rigorous, by and large most of them were clueless. As for personal recommendations, one of the features of the huge fake "University Degree Program" was that they provided enthusiastic letters of recommendation from their (non-existent) faculty: "I have been teaching in universities for thirty years, and Mr. Insertname is, without a doubt, the finest student I've ever had..."