The Abandonment of the Gladius for the Spatha - Why?

[Thiudareiks Flavius]

If I am not mistaken,..the Roman empire went more and more to Cavalry formations. As cavalry became more and more the force of choice on the battlefield, the Spatha would be the preferred edge weapon due to its extended reach I would think as compared to a gladius if one were looking to engage an enemy on horseback or running down a dismounted enemy. Especially after the Spear or lance was used and dropped.

Yes, but the spatha had always been the sword used by Roman cavalry. The question here is why was it adopted by the late Roman infantry as well.

Could it be a logistical factor in that the smiths were mass producing one type of sword for ease of production?

Maybe, though this had never been a problem for Roman military manufacturies before. I'm still inclined toward it representing part of a change or adjustment in battlefield tactics myself.