In retrospect Renault-Nissan suffered from what is known in business school jargon as a “key person problem,” said Christoph Schalast, a mergers and acquisitions lawyer in Frankfurt who also teaches at the Frankfurt School of Finance & Management.
“Everything depends on one key person,” Mr. Schalast said.
Mr. Ghosn’s power and unusually long tenure may have prevented the alliance from evolving as Nissan became by far the bigger and more profitable partner, yet Renault exercised more control, a situation that some in Nissan grew to resent, according to interviews with three former Nissan employees.
Now that the Ghosn era appears to be ending, Mr. Schalast said, Nissan and Renault “should establish a new, more cooperative management team which is not dependent on one person.”
In April 2017 Mr. Ghosn ceded some power on the alliance board. The rules were changed to give four votes to Mr. Ghosn and four votes to Mr. Saikawa, the Nissan chief executive, according to regulatory filings by Renault. The other eight members — four from Renault and four from Nissan — had one vote. If there was a tie, Mr. Ghosn decided.
But Mr. Ghosn was also leading an effort to push the two companies closer together. In September 2017 the Renault-Nissan Alliance announced a plan to save an additional €5 billion a year, or $5.7 billion, by cooperating even more closely on buying parts, designing motors and other components, and sharing manufacturing expertise.
According to the plan, almost all of the vehicles produced by Nissan, Renault and Mitsubishi would be based on four so-called platforms, combinations of chassis, engines and transmissions that are largely invisible to consumers. Two-thirds of the vehicles would use common engines, up from one-third in 2016. Sales would rise to 14 million vehicles a year by 2022 from 10.6 million in 2017.
While Mr. Ghosn insisted that the companies would retain their autonomy, the debate continued. If Nissan provided damaging information about Mr. Ghosn to prosecutors as part of an effort to dethrone him — as many Ghosn sympathizers believe — it backfired badly.