The reason for that is that Roger Moore was not James Bond, but that James Bond was, for a time, Roger Moore.
During my work for Ofqual -the examinations regulator -I had occasion to meet and work with the actor Derren Nesbitt, who was running a small Awarding Organisation at the time. During lunch, amongst many other anecdotes, he told me that he had once been standing on set with Roger Moore, who turned to him and said:
“You know, Derren, I’m very tall, very suave, and have a very good speaking voice. I’m just terrified that one day they’ll find out that I can’t f***ing act!”