It was "in vain" cause you failed to explain what this "much more" is. What prevent the "Ambrosini 7" series to be a fighter?
If you did not understand this by yourself it is very difficult that I can make you understand: but as I don't want to talk about Young's modulus, shear modulus or Bredt formula, and many, many other technical matters, I pose just two "minor" questions:
1 st - could in those days (about 1940), the Ambrosini factory to establish a serious quality control for the woods (Italian forests are not Russian forests) and for the glues used ( poor self-sufficient materials, "materiale autarchico" in italian) and, expecially in the bonding process, to guarantee to have thin wings perfectly built to resist to the stresses by the loads of a speed of 900 km/h?
I'm not talking of a single prototipe, perfectly built and lovingly mantained, I'm talking of numbers.
2nd - After one or two weeks of desert climate ( or even Sicily for this matter, more than 120 °F in summer....) or fog and ice in Northern Italy, G's, poor field maintenance, sand, rough landings, an enemy bullet maybe two, two or three sorties a day, was to be this wooden wing still in its original shape?
If your answers are yes, the Ambrosini 7 had passed just the first examination ( many other would have followed) to be graduated as "fighter".