I believe the Maxell commercial was copied by comedy shows and films for years after that, which made the commercial itself a pop culture icon.
As for the use of the classical music, I don't believe this took anything away from those pieces of work at all. Sure, it commercialized them, but it introduced that style of music to a wider audience. It's part of the reason I love classical music to this day.
Take a look online at a video on Youtube that uses music and in the comments there are tons of people asking what the song is that was used. It's the same idea. Hearing it causes people to gain an interest in it and want to hear more.
Can you think of any commercials that you heard music on that inspired you to look into the artist and want to hear more of that style of music?