Quote Originally Posted by Baryonyx Walkeri
Perhaps it was to expensive? anyway many tech were lost since the romans recruitted Barbarian units....
That is a common misconceeption which is basically wrong. From the early principate onwards over 50% of the army and more of the marines and navy were "barbarian" non-citizens, the auxillary infantry and other service branches were excellent at Romanising their recruits and this is not why technology or fighting tactics degenerated.

Further, Lorica Segmentata was produced by Gallic or Germanic smiths in the Rhineland, actual Roman metal working was generally poor by comparison.

The reason it was dropped was because it was expesive, difficult to maintain and manufacture, not to mention providing overall lower protection than hamata.