Why is Six Sigma so popular?

Six Sigma methodology has recently gained wide popularity because it has proven to be successful not only at improving quality but also at producing large cost savings along with those improvements. Some spectacular Six Sigma "success stories" at large corporations have been widely publicized and they captured the imagination of many business leaders.
Many other companies have also reported savings of literally astronomical magnitude after incorporating Six Sigma methodology across their manufacturing facilities. For example, Motorola (the leading member of a consortium of companies that developed the Six Sigma approach) reported over 11 billion dollars in savings since Six Sigma started spreading over its factories 12 years ago. Allied Signals reported over 1 billion dollars in cost savings due to Six Sigma in just a few years.