You people are too picky. Brown's work is easy to read mindless fun that is easy to pick up and put back down, written especially for the ADD lifestyle auidence that he's targeting (YUPPIES especially). James Patterson is even worse (Can you really call one page a "chapter"?). Structurally, he's a below average professional writer, but his ideas push intersting hot buttons that tend to appeal to a wide variety of readers.
If formulaic didn't sell, John Grisham would be a nobody. Brown is just walking in those footsteps and many other writers who eventually fall into this pattern because it's easy for their readership to digest when the structure is the same from book to book.
Personally, when it comes to that kind of escapism (I do a lot of technical reading so this kind of fluff is a welcome break), I prefer Clive Cussler. Better pacing, same story structure, but a little more variety on the backdrops, and better central characters (Dirk Pitt, Admiral Sandecker, & Al Giordini are hashed together stereotypes, but extremely fun to read). As long as you are willing to suspend disbelief and accept the convenience of a familiar structure from book to book, these books are a lot of fun.
That said, I enjoyed A&D, and Digital Fortress wasn't bad. TDC & DP I found to be subpar.