Actually, it's not a matter
Actually, it's not a matter of opinion. Fiat DID save the Miata. I have followed this story for a number of years. When Mazda did a market study, they could not justify the dollars required to develop the new car, and would have let it die (as they did the RX7), if Fiat had not come along and parterned with them.
And while most people assume that Fiat came along later and just modified Mazda's design, nothing could be further from the truth. In fact, it was Fiat that decided MAJOR design elements of the car: the weight reduction, long hood, lowered engine location, windshield location and angle. Fiat dictated a lot of design elements because they wanted the car to fit the design profile of the Alfa romeo that the car was originally planned to be.