The attitude that "the last important music was written by dead people", or past a certain time limit, should have been obsolete decades ago. It astounds me when I hear that assessment today, it's musical bigotry of the most ignorant kind. Hopefully the day is coming when non-musicians will come out of the Dark Ages and accept Rock/Metal music as they would any other genre. A dead giveaway of the musically uneducated person is his or her derogatization of the term "popular music", especially when used as an umbrella to lump in Lady Ga Ga with Uli Jon Roth. Though there are many Rock/Metal songs that stay within the timeless I-IV-V, "popular" framework, there are nearly as many exceptions to this adherence as there are examples.
It's humorous to witness how the snobbily-inclined fasten on the more popular side of music genres, as though any individual bids to popularity prove the invalidity of that whole genre. I've had to deal with people, including some "classically trained" professionals, who had an inordinately hard time listening to Rock/Metal music, saying things like "why does the guitar have to sound like that" and "what's that obnoxious sound?". If they'd let themselves have any perspective, they'd realize that people were saying the similar things about Beethoven's Eroica (too noisy, too epic), and later whining to the high heavens about the introduction of the Wagner tuba (such an unpleasant roar! oh dear!).
After having pored over biographies and music of the great composers, I learned something that completely affirmed my regard toward Rock/Metal music. Beethoven, Schubert, Mozart...they all wrote with money and popularity on their mind, most of the time. The masses, whom go out of their way not to think too much, try to pretend a movie like "Amadeus" or "Immortal Beloved" is fact and not fiction. Take for instance the Hollywood faerie tale that Mozart suffered from poverty because his music was "too advanced", or "revolutionary". What a joke. Mozart lived it up; his letters and myriad testimonies from contemporaries bear that out. He had a very bad habit of getting a big commission, blowing it on high living, then borrowing and blowing it all over again. There's also the myth that he was "woefully underrated in his time". Mozart was recognized as a spectacular composer all across Europe, the only amount of "obscurity" he might have experienced was because Joseph Haydn came before him, and invented the templates that Mozart wrote from.
And Mozart, just like the rest of the greats, mostly wrote music because he was either getting or expecting to be paid. True, there are many compositions that he and the other "classic composers" wrote just out of love for the art; but it's notable that most of the stuff he is remembered for, (not just the catchy stuff), music like Eine Kleine Nachtmusik and the Requiem were paid for in advance. The big knock against popular music, the idea that money and fashion rule over substance, looks pretty silly when viewed in this light. Not to pick on Mozart, a terrific composer of course, but he wrote within the Sonata framework, which is a very set style that was all the rage in that century, (and still knocking them dead well into the 19th century). It was the style that paid.
Tell me the Allegros of the Sonata Facile, Rondo Alla Turca, Eine Kleine, etc. aren't Poppy. There are dozens of other examples.
To quote Jon Lord, as fine a musician as I can think of, "our (Deep Purple's) music is just as legitimate as Beethoven's". And for its place and time, it most certainly is.