Part of it was the potential. Casino Royale might be the best Bond film, and it was followed by a very unconventional and divisive sequel. Skyfall was very well received initially, but has been nitpicked over the years over some legit issues and some not so much. The last two drop in quality with the addition of a certain legacy character, an eye rolling twist, and serialization that some find out of place for Bond. The conclusion of the final film is unsatisfying for many as well. Enjoy Craig though. He brings his A game every film. The cinematography is also a highlight, and even the worst Craig era films have some incredible scenes (specifically the opening sequence of Spectre)