Run out of combinations of musical notes?

It never ceases to amaze me that we haven't run out of all the various combinations of musical notes by now, and people can keep on managing to come up with popular, original (and yet similar, so they fit into their various genres) enjoyable ditties...I bring up this topic as yesterday (some of the guys behind me keep a radio on all the time, pretty quietly, but we do get subjected to a stream of pop songs all day) we heard the Queen song "Under pressure" which one one of my colleages mistook for Vanilla Ice's (real name Mr Van Winkle ;) "Ice Ice Baby" both of which have an extremly similar repeating series of notes (click them to listen if you like and compare)...

Apparently, Mr Winkle originally defended himself (on MTV) saying that there was no way they were the same and he'd just come up with the same series of notes and timing accidentally, however Queen didn't see the funny side and things very nearly ended up in court, in the end he just paid them an "undisclosed sum" (very quietly) and got on with his career...finally confessing publicly (but only *this* year) - "What happened is I was trying not to get sued and it didn't work. So yeah, they're the same songs, in case you were wondering"...Quite nice of Queen not to kick up a bigger fuss about it...

As a race we have been stringing together tunes (Solfège) for many thousands of years, so frankly, I wouldn't be surprised if people started to tread on each others toes a little bit by this stage, but it really doesn't seem to be happening or more high profile cases like this would surely exist...? Or perhaps what has happened is that many of the original (and pleasing to the human ear) arrangements of notes have already been done and all that's left is moving chunks of them around a bit (and changing the words on top)...

The number of cover versions in the charts would hint that true originaliy, musically rather than lyrically, is something that may be a rare thing, looking forward...