During my slow times at work, I've been reliving some old 1990's TV commercials via YouTube, and have noticed a pattern.  All the way through about 2000, many companies used an original, catchy little tune to advertise their product.  A prime example is Coke's "Always Coca-Cola" theme.  It was memorable and original.  Now they've shifted to a more edgy, rap-oriented style of advertising.  Same with McDonalds...they've done away with universal appeal in favor of a more hip, stylized type of advertising.  This trend was also noticeable in sporting events.  Remember "Roundball Rock", NBC's classic basketball theme that never failed to get the adrenaline pumping for a Sunday afternoon double-header?  It has been replaced by a series of pop R&B songs and a more recently a theme song, that while original, is drab and has no energy.

Why do you think companies feel the need to be edgier, more "current", and keep up with the latest trends?

Sorry that I don't know to the answer to your question,

but a good 90's commercial with a good jingle would be the old mentos commercials.

The freshmaker.