From the perspective of a skilled armorer, chainmail is actually easier to make, since the rings can be made by apprentices or (in Roman times) slaves. Plate requires far more man-hours from a master smith, and it needs more work to make it fit the wearer well.

"Chainmail" is actually a neologism, invented in the days when Victorian scholars were obsessed with classifying everything. At the height of it's use in Europe (800-1300) armor made of interlocked rings was just known as "mail"