You are right about the quality of Ali extrusions.
Where I work, they have their own extrusion plant.
They choose to make it faster rather than straighter/flatter etc, but sometimes it is more of a matter of the extruder operator not knowing any better.
Extruding seems a simple enough process, untill you get involved with it, and then discover the idiosyncrocies of the process and what the customer is prepaired to pay.
Even the quality in the finish of tooling plate (7079, 7089) has dropped considerably in the last 10 years.