Mail replaced segmentata? Why?

[Dan Howard]

Lusitano wrote:
Could the replacement of the segmentata by the hamata be somehow connected to the slowly decline of the roman empire?

In a very simplistic sense I guess I'm saying "yes".

Hardly. Segmentata was faster and cheaper to produce than mail. Do you have any idea what was required for iron age cultures just to produce iron wire? The quality of wrought iron had to be much higher than that required for plate. Poor wrought iron cannot not be drawn into wire.