The same might be said of the car business. It’s easy: You just design and build great cars.

Of course, it isn’t that simple. As the recent misfortunes of General Motors (GM) and Ford Motor (F) demonstrate, something as straightforward as installing foolproof ignition switches or accurately calculating fuel economy can elude the most experienced of automakers.

When it comes to marketing cars, there is an emerging debate that can most succinctly be described as mass vs. class.

On the mass side is analyst John Murphy, author of the long-running “Car Wars” study for Bank of America Merrill Lynch. Murphy is a fan of new models, the more the merrier. He has consistently demonstrated that market share is directly related to the number of new models a company introduces and the speed with which it refreshes them. While he concedes the importance of mix, pricing, execution, distribution, and brand power, he argues that the more rapidly product lines are expanded and refreshed, the more rapidly sales will grow. “Our measures of replacement rate and showroom age are the major driver of market share gains and losses,” he writes. “Successful new products drive higher market share.”

Leading the arguments for the class side is longtime marketing consultant and self-styled industry curmudgeon Peter De Lorenzo. De Lorenzo, who is based in Detroit, leads the AutoExtremist blog, calls himself “a purveyor of the bare-knuckled, unvarnished, high-octane truth,” and has been a rigorous defender of brand integrity. “How a brand is perceived can make or break a car company, regardless of how long and illustrious a run that brand has enjoyed up until any given point in time,” he wrote in June.

De Lorenzo has been a persistent critic of luxury brands that use new models to grow volume. He believes they are compromising their identity by using their brand for vehicles that have no connection to heritage and history. “They believe that if they cover every niche in the market–both real and imagined–it will ensure their survival and profitability,” he contends. “But it doesn’t work,” he writes. “There are painful ramifications that come with their actions.” 

One of the unique strengths of “Car Wars” is its distillation of competitive intelligence, press clippings, speculation, and rumor analysis into a rigorous analysis of future product trends. In the most recent edition covering the years 2015 to 2018, Murphy identifies by model name and segment, every redesign and new model coming to the U.S. market. He sees a surge of new crossovers vehicles bearing the badges of luxury manufacturers that previously concentrated on sedans, coupes, and sports cars–among them Audi, BMW, Jaguar, and Bentley–and writes approvingly about the positive impact on sales. “If the numerous new German Lux CUVs are well received in the market,” he writes, “there may be some upside risk” in the market share of European OEMs.

Such product line extensions into unfamiliar segments by long-established brands induce a state of near apoplexy in De Lorenzo. Brandishing no research but effectively flexing his instinct from years in the business, he argues that automakers–particularly those with a racing heritage–should stick to making cars and leave crossovers and SUVs to the likes of Jeep and Land Rover. He gets especially vitriolic in discussing the strategies of the fast-rising German luxury makers, which seem to keep adding more body styles–BMW Active Tourer anyone?– aimed at freshening up their product lines and adding incremental volume:

• “[Audi] seems to be falling victim to the disease that’s infecting all of the German brands of late, the dreaded being all things to all people daze that leads these manufacturers to drop their guard and make mistakes.”

• “Almost everything that made BMW a BMW has been lost in translation.”

• “When [Mercedes-Benz is] off, well, they can stink up the joint like no other. Daimler is forced to stretch out its model lineup because it’s trying to fight a brutally competitive auto world without the resources of the other auto manufacturer conglomerates.”

Murphy and De Lorenzo agree on some things. In the latest “Car Wars,” Murphy singles out Ford and Honda for their speedy replacement of existing models, and predicts that each will gain half a point of market share over the next three years. De Lorenzo likes both companies too. But he worries that if Ford “allows itself to get complacent, its prospects will be less than stellar,” and wonders about Honda, “will it stumble again and lose its way?”

Who is the winner in this faceoff? The Car Wars analysis has a lot to recommend it. With statistics on new models going back to 1987, it possesses unusual depth. It is even-handed, and if it occasionally misses some fine points, it projects a reasonably accurate view of a company’s relative position in the market compared to its competitors. But Car Wars may be of less value going forward. As foreign automakers fill out their product lines and as all manufactures achieve more consistency in their product renewal cycles, there will be fewer big shifts in market share.

De Lorenzo plays favorites and rarely lets the facts get in the way of a good argument. German luxury car makers are enjoying record years, and despite some grumbling about the quality of lower-priced models and unconventional body styles, they appear to be holding on to their existing customers at the same time as they attract new ones. Passionate though he is, De Lorenzo can shift gears. At one time a ferocious opponent of Porsche’s diversification away from sports cars into SUVs and four-doors, he now praises the company for being “relentlessly focused” and “peerless” in its execution.

And in the end, it is execution more than anything else that determines success or the lack of it. Look at Tata, owner of both Jaguar and Land Rover. Jaguar concentrated on sedans and coupes for its entire life and nearly expired. Now the first Jaguar crossover, the XQ, is due in 2017. Land Rover, on the other hand, has stayed focused on SUVs and thrived. Even its Sport model is expedition-capable and there are no signs of an active tourer on the horizon.