You’re absolutely right, as myowz pointed out, it was ignored with G/Alphabet, but it would funnily confusing to say “He works for a MANGA (or MAAAN) company” to someone…
Google did not rebrand itself though, it's still Google. It's the holding company that owns Google (the company) that's called Alphabet. In contrast, Facebook does an actual name change now - there'll be no company named Facebook anymore, just a product.