It’s been said youth is wasted on the young. Apparently, a lot of advertising dollars are, too.

As the leading edge of the Baby Boomer generation, aged 41 to 60, nears retirement age, marketers have been shifting their focus and pouring billions into appealing to more youthful consumers.

Models with gray hair have been banned from commercials, and auto makers have been racing to develop new vehicles and features that appeal to younger, hipper buyers.

Toyota was so despondent over the advancing age of its customer base it started a whole new “youth” division: Scion.

Honda pulled out the stops to develop the Element, designed to be a dorm room on wheels. Numerous other youth-oriented products are in the pipeline at various auto makers, including the new Dodge Caliber.

The conventional wisdom is that once consumers hit their 50s, the only products they buy are pills for their ailments and hip replacements.

Now, a new study by AutoPacific concludes automotive marketers are paying too much attention to youth-marketing efforts when they should be focusing on Boomers.

The reason is simple: Boomers have money to spend on new vehicles. The youth market does not.

Baby Boomers by far are the most affluent Americans, with $2 trillion in annual disposable income, AutoPacific says. What’s more, they are expected to grow even wealthier as they inherit money from their elderly parents.

And, most importantly, they are expected to continue spending money on new cars and trucks well into their golden years, buying the “aspirational” vehicles they could not afford when they were younger.

The average American household purchases 13 cars over a lifetime, and seven of those are purchased after the head of the household turns 50, according to AutoPacific.

Yet only about 10% of advertising money currently is aimed directly at consumers 50 and older, Auto Pacific says.

Meanwhile, consumers in their 20s are looking increasingly like a bad bet for big-ticket items. Books such as Generation Debt chronicle how an unprecedented number of young people are drowning in debt, entering the workforce overloaded with college loans and maxed-out credit cards and burdened with poor credit ratings.

I have done my own 20-year study on the buying patterns of the youth market, personally housing a Generation Y consumer since infancy.

My study subject, currently a college student, cannot afford car insurance – more than $2,000 a year for a 13-year-old car – much less a $300- or $400- per-month car payment. The most expensive item he purchased during the past 12 months was a $375 pool cue. (He says it was a great deal.)

Certainly there are thousands of affluent 20-somethings who can afford a new car and the pricey insurance that comes with being young, but the idea there are millions in such cushy circumstances stretches credibility.

The Honda Element attracts buyers in their late 40s, not their 20s, and more than a few senior citizens are buying Scions.

Auto makers need to start rethinking their marketing and product-development strategies.

They need to understand the guys in that “dorm room on wheels” are older, but not aged. They merely are biding their time until they are old enough to marry Anna Nicole Smith.