Kevin Bacon has been starring in films for around 40 years. There have been tens of thousands of films made during that time, but the number of records released would absolutely dwarf that figure. Most films also feature a cast that is much larger than the number of musicians who are given credit on any given album, so it's obviously much easier to connect the dots between major film stars than it is to connect them between musicians who played together or recorded together. Secondly, many film stars appear in action movies, comedies, dramas, romance movies, thrillers, etc., so there is a much greater degree of overlap when it comes to film stars than there is when it comes to musicians where the wide majority are more comfortable assuming a certain role playing a certain style. "Rock and Roll" has been around for a lot longer than Kevin Bacon's career. And in that time, it's grown and morphed, progressed and evolved, developed and changed so much that early rock doesn't sound all that much like the type of rock being produced today, of which there are many different types. In all honesty, if anyone were to attempt to point to one single person who has played a hand in a host of different musical acts, bands, endeavours, etc., that person would in all likelihood suggest someone like a producer rather than a single musician as producers tend to work with a much wider range of artists than the average musician does, their reputation is usually built on a history of working with successful musicians and bands, so they tend to have a much wider circle than any individual musician could realistically hope to create for him or herself. It's an interesting question and there are a few names that spring to mind, but I don't think that anyone would really be able to drop a name that could be connected to Classic Rock musicians, Pop-Rock musicians, hair-band musicians, alternative rockers, heavy metal artists, etc. Rock music is more about birds-of-a-feather type of thing, whereas producing is all about what you've proven yourself capable of when it comes to producing a successful record.