I think segregating the brands was a mistake unless they're deliberately packaging them up for individual sale.

If that's what they're doing, they should probably get to work on that ASAP.

If it's not what they were trying to do, then they fucked up because as I understand it, fleet economy/emissions averages require that they sell efficient vehicles even under specialty marques . In other words, as I've said before Jeep actually has to sell trash like the Renegade in order to legally sell the Wrangler, because it's just not reasonable to expect an extreme terrain vehicle to also sip fuel like a city car. Ram has to sell huge trucks (and not compacts) because again, regulations require small vehicles get exceptional fuel mileage and a small pickup can't really compete with a city car.

Under one brand, the highly efficient electric/hybrid/compact cars would offset the necessarily inefficient heavier duty vehicles - but since the brands are distinct they are limited in what they can legally sell.

I may be misinterpreting that, but it's what I gather.

Anyway to answer the question that was asked; the first thing FCA can do I believe is go fuck themselves because they are the absolute most frustrating company I have ever personally dealt with, they lie to their customers and provide no followthrough on actual promises they make. They also do this in violation of legal precedent but that's a much deeper topic.

After the present owners violently fuck themselves to death with an assortment of very rusty farm implements and aggressive sea creatures, the hypothetical new owners of FCA group could either proceed with the business of selling off the individual brands or, if they wish to remain as one company - they could work to unfold the mess of separating the brands by turning every brand into a model name instead. Instead of the Jeep (brand) Wrangler (model) Rubicon (package) it would be the FCA (brand) Jeep (model) Wrangler Rubicon (package) and at the same time drop name-diluting concession models entirely like instead of the Jeep (brand) Renegade (model) it would just be the FCA (brand) Renegade (model) - that way the name Jeep doesn't have to get devalued by little useless city cars that think all wheel drive and 7" of ground clearance makes an off-roader.