In addition, there are physical limitations to how much automakers can increase a platform in size and still use identical parts, engineers acknowledge.

“With a common architecture, I think the industry’s been good about having flexibility on width within 2-3 ins. (51-76 mm),” Chernoby says. “You can hold a lot of the car common and still vary that much. But anybody that tells you they’re varying 4, 5, 6 ins. (102-152 mm) in the car, then you should ask, ‛Show me what parts are common when you’re done.’”

It’s even more difficult to engineer common in an age when multiple powertrains are required, including hybrids and battery-powered, the Chrysler engineer notes. “The technological evolution under the hood with engines and transmissions is moving at one of the fastest paces we’ve ever seen. That is adding a lot of challenges for us in terms of holding that layout common.”

These huge global platforms come with a high risk/reward quotient on quality, as well. One defective part could trigger a massive global recall that overnight could obliterate any upfront cost savings.

That means much more will be asked of parts makers in keeping close tabs on manufacturing down through the lower tiers of the supply chain to limit exposure if a recall is required.

“You have knocked-down kits being shipped to smaller markets. You might have swing capacity (where) you are exporting parts to another part of the world,” Andrea points out. “You have to be able to trace parts back to all those scenarios.

“You look at all the (initial) cost savings and all the other advantages over the years, (and) you just don’t want to have that one recall situation that can wipe (that) out.”

But using the same parts and identical architectural strategies gives automakers more time to perfect designs, potentially reducing recalls overall, engineers argue.

“Typically, diversity does not go very well with quality,” Renault’s Billig notes. “And by reducing this diversity, we have more time to focus on the maturity of our solution, on our processes and the repeatability of what we are doing.”

Thai-Tang agrees. “Net-net, we think it’s actually a good thing for quality.”

In the end, the potential advantages outweigh the drawbacks. Even though engineers know there are huge roadblocks to designing the truly scalable, flexible vehicle platform with a high percentage of common parts, they’ll keep trying – and ultimately push the bar a little higher with each attempt.

Asked if scalability is the future, Renault’s Billig says simply, “We think it is.”

AlixPartner’s Hoffecker sums it up this way: “Everybody’s (wanted) to do this for decades. The reality is it’s become more and more important as we get more and more global products, and consumers want and desire more differentiation and price points.

“It’s almost becoming a requirement.”