[pkd]

I have never used a fountain pen with a glued together nib and feed. The ones on the top of the page aren't glued together, they are the screw on type. These are generally found in hand-tuned pens (like the Edison Noveau) or premium pens (like Pelikan MX00 series).

You can still adjust the flow of the nib without tampering with the feed by just using a brass strip and running it through the slit in the nib (to increase the flow). I have never wanted to decrease the flow of a nib unit.

What you are saying is true though. Ebonite feeds have their advantages, like you can heat tune them as well to fit to a certain nib shape.