Shōgun is a great show and all, but I don't get why they didn't just give the characters the same names as the real people they're based on

Sure much of it is fictionalized, but a lot of is based on true events and most of the central characters are based on real people. There really was a powerful samurai who supported the heir of the previous ruler, which put him at odds with the government (Tokugawa Ieyasu), there really was an English sailor who traveled to Japan, was renamed Anjin and made a samurai (William Adams), there really was a highborn woman who was a Catholic convert and played a key role in Japan's political turmoil back then (Hosokawa Gracia), there really was a rival to the main character who had sided with the government (Ishida Mitsunari), he really did have a friend who was a fellow samurai lord afflicted with leprosy (Ōtani Yoshitsugu). The list goes on! If you're going to make these characters so closely to whom they're based on, why not just give them the same names as the real people as well? 🤔