Regarding the Annual Model Change business paradigm he created, Harley Earl boldly announced in 1955 that: 

“our big job is to hasten obsolescence. In 1934, the average car ownership span was five years; now it is two years. When it is one year we will have a perfect score.”

In the annals of modern auto history it's a fact Harley Earl originally sold the idea to GM how they should be the first auto manufacturer to recognize the implications of visual appeal and/or design. By Mr. Earl first introducing the "Annual Styling Model Change" (and starting to implement its use within GM) he initiated a pattern of attention to consumer needs which was then manifested in every modern product General Motors was to design and build thereafter in the future. Today, the tradition of the Annual Model Change helps shape products throughout American industry; ranging from Apple iphones to earth-moving tractors. This very business activity, with its accent on continual design improvement has stimulated product improvements and sales of everything from the most up-to-the-minute computer, sneaker, cell phone or car, felt with equal passion from Shanghai to Chicago, is the enduring handiwork of Harley Earl, the first engineer of desire. Needless to say, it is the lifeblood of the American automobile industry and, therefore, has become a key factor in our world economy, too. 

In 1956, Harley Earl made the following statement, quoted below, on two very powerful forces he had originally began introducing inside GM as far back as 1925 when he was hired into this company as a "consulting engineer." Between this time and the early 1950s, Earl and GM made a practice of never publicly promoting or sharing any "automobile design based business philosophies" on account of how Earl's design sword was at the top of the trade secret list General Motors continuously implemented to rapidly gain valuable market share points, so fast, over all their largest competitors. And Earl's new profession [automobile design] dramatically impacted other areas of manufacturing GM was largely concerned with during the mid-20th century years: trucks, trains, airplanes and buses...etc. By the mid-1950s GM was way out in front (in the bus industry alone, they had over an 80% market share) and nearly had a 50% market share of the automobile manufacturing business. So, Harley Earl --- the world's pioneer of the Automobile Design Profession --- began to publicly take some credit for his inventions...one of which is simply outlined below.  Naturally, many other powerful men inside GM (especially the rogue underlings coming up) held contempt since none of them had any dramatic milestones under their belts: 

     "In styling, however, where noticeable change must come annually, it amounts to dynamic obsolescence– the creation of a desire on the part of millions of car buyers each year to trade in last year's car on a new one is highly important to the automobile industry. The annual model change is directly responsible for this yearly trade-in situation. Since the design of the automobile is the first thing the buyer sees, the stylist is more continuously involved in the annual change. The importance of engineering changes, however, cannot be over estimated, but by their very nature they cannot be changed annually as much as can the appearance of the car.

      Thus, the design of the car can be a persuasive tool for inducing car buyers to get rid of the old and buy the new...." 

Another thing that's been cloaked by GM's spin doctors over the last forty odd years has to do with this company having ever experienced a "monopoly" like status. That's because GM's wizard attorneys have never allowed anything historical to flow out of this company on this fact...let alone the truth behind what really caused it to happen in the first place: Harley Earl and/or his design sword of power, is the where the real story lay buried. In other words, one could add two word to the first sentence of this article below from 1959 relating to how GM very much had a design monopoly, "the world's largest ' auto design ' manufacturing concern."

Look at the facts for what they really are: Earl first created Detroit's dependency on design and by the time he stepped down from the auto business he had taken the global automobile world into the design business. It's natural that every other major auto maker adopted his auto design rules and principles because it was the main reason GM became the No. 1 auto maker and launched themselves so far out in front of all their competitors. 

Although the Annual Model Change and/or Design Obsolescence have been deemed before as "the lifeblood of the auto industry" by some business writers and/or university business professors, most Americans find this business paradigm to be extremely esoteric. In any event, this body of knowledge is a giant sales weapon that Detroit's auto makers primarily ignore today to gain market share (a colossal mistake, and the main reason America's auto industry is in such dire straits):

Here a couple of news stories on Mitchell climbing into the top spot of the auto design industry and/or into the chair of the world's greatest car designer's seat of power. Of course they were spun to insinuate that "Mitchell was the chosen heir apparent protégé" by Harley Earl. The fact of the matter is that Earl had no intentions of retiring at 65 years old, but was deposed in a silent coup by young turk GM execs who got the upper hand over the aging mentor Earl and forced him into retirement.