"I don't know how the decision was taken, but in 1952 it was decided to use 2,500 Empire tractors bought in the United States to build a small rural truck," aeronautical engineer Raúl Salvador Gómez told La Nación. In post-war times, the government intended to leave assembly behind in order to produce entirely domestic vehicles. It took only 87 days to build, on the Cordoba site where the Pulqui II had made its maiden flight months earlier. Despite having reached 120,000 units and retaining nearly 80% of the diesel market, in 1980 the civil-military dictatorship decided to close the state-owned company and put an end to the history of the country's most gaucho and hardest-working truck.

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Note added at 14 mins (2023-02-22 18:44:49 GMT)
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Nothing to do with diesel consumption, it's about the company's market share of these vehicles.