Will economies of scope drive more mergers in the automobile industry?

The WSJ reports that the goal of the proposed merger of Fiat Chrysler and Peugeot is to increase profit. My question is, why would the merger => more profit. I see two alternatives. One way that a merger might increase profit is the merger's impact on the 5-forces. The combined market share of the two firms might gives them more bargaining power over buyers and sellers; it could reduce rivalry within the industry and it could make entry more difficult. The second way that a merger might increase profit is because the larger firm is able to take advantage of economies of scope. The article reports some evidence that economies of scope may be important.

"But Sergio Marchionne, the legendary Fiat Chrysler chief who died last year, was a persistent advocate for deeper consolidation. He drafted a 25-page manifesto in 2015 imploring the industry to share the costs of developing parts most customers never notice, such as engines in small cars.

“'It’s duplicative, does not deliver real value to consumers and is pure economic waste," the report said."

The previous mega-merger that was supposed to herald major changes in the structure of the industry was between Daimler and Chrysler two decades ago. That merger did not end well.