I agree that Buddy Guy is the last remaining elder statesman of the blues genre. But to suggest that he would "replace" the King, or usurp the throne.... No, I just don't think so. Buddy Guy was a contemporary of the King, and even if it were a literal position to be filled, I don't think Buddy Guy would take it.
There are some great Blues guys out there, (as well as a couple of Blues gals), each contributing their bit. And let's not forget that not only are some contributing, but some are also mentoring; such as Buddy mentoring young Mr. Quinn Sullivan. I've seen him, the blues are in good hands.
Then there is Griff Hamlin, Marty Schwartz, and, in turn, all of you. Keeping the blues alive. Nay, did I say alive? Not merely alive, but if national trends are too be believed, growing in popularity.
There are those that will always stand out, and stand apart. BB King, and Buddy Guy for the blues, Gene Krupa and Buddy Rich for jazz, and there will never be a progressive rock musician/composer/performer that will match Frank Zappa. These people are unique talents who did not just play music; they lived it. Music did not make them what they were, music was what they were. They were the pioneers, the front runners, laying the path for all who follow.
I do not believe there will ever be another "King"; some people will never be replaced, but I do believe that the blues will live on.
Rest in peace, Mr King, you were an inspiration to so many, and have given so much to the world. You taught us that the blues isn't something to be merely played, or heard, but to be fealt deep in the soul. In short, your music touched the souls of all who heard it. What better gift can any man give mankind?