Music is a very broad term, and music can be used for many things. Expression is one of them, telling a mesage is another.... fun and jokes are also done through music and this is completely valid. A large portion of Steve Vai's music is about fun and little jokes and stuff, and people say "hey thats not music", well yes it is music, its just a different form of music.
Money is shallow to a degree but not entirely, most people in this world strive for money because they've been bought up to think that money will make them happy, they watch all their commercials and imagine the excitement of having everything... but money is nothing, its positive human interaction and other such things which make people happy... if some people dont realise it then its not their fault, its just what they have been fed by our shitty over commercialised society. What im saying is that really they are striving for happiness and enjoyment from life, under the illusion that money will achieve this, which for many people this isnt true.
Fame and success, its an interesting one, we humans need to have aims and we need to reach those aims. For some people they grow up believing that the people in the popular bands are the best musicians, and they strive to reach such 'heights'... and when they succeed they feel extremely good about themselves because in their mind they have reached the top, they look around and see everyone loving them and think that means they are the best musician ever. But you have to put this achievement into perspective, these people put a LOT of effort in, theres a lot of chance and risk in developing an 'artists' style and picking the right songs and getting the right publicity and putting on a good live show (which in pop terms means lots of dancers and pretty stuff).. and the fame (ie their sense of achievement) is their reward. Is that so shallow? The basic idea is getting aims based on what you think the best is you can achieve, and then reaching that mark. I dont think its such a wrong mode of thought, the problem is, again, how we are bought up to believe certain things (and these people believe being famous is the highest point you can reach).
Personally i dont agree fully with a lot of bands who set out to 'tell a message' either... what i get from music mostly is the art side, the expression, the emotions.. and as such 'messages' dont fit into what i liek so much.. i prefer to hear stories that represent situations or feelings or whatever, not something like "be good to your mother" (i wonder if any band has ever expressed that message in their songs?). But in no way am i saying expression is better than telling a message... they are simply two different approaches and uses to music, of which i like one approach better than the other for no reason other than my taste in music and what i need/expect/want from music.