Leather only armor in roman times is a somewhat disputed topic, but, in mantaining a somewhat coherent view, there were light armors in post-roman times, but no leather armor.
So, what I think is that, when (for example) a Milanese type armor becomes available, there should be better and more economical types of light armor. If the loom was invented, a gambeson would offer better protection be more mantainable and probably be more economical to produce than a leather lorica segmentata.