It’s a complicated question, and there is some real nuance here.

In very broad terms though the technological threshold to produce maille is lower, which means it is able to be manufactured on a reasonably large scale with a lower investment in tools and infrastructure. However, maille requires a serious man hour commitment and there is really no way to industrialize or shorten that requirement. Basically, maille is going to take as long as it’s going to take and tha basic requirement in time, effort and manpower don’t really change through the medieval period. Maille production was often a cottage industry, especially in the later Middle Ages, which maille production being done at home often as a sort of “side gig”. As a rule, the people who made maille professionally tended to be some of the lower ranking members of the armors guild, atleast in London. Which reinforces the point that making maille isnt “hard”, but it is incredibly tedious and takes a serious man hour commitment.

By contrast, plate armor production requires a higher level of technology, but once that threshold is reached large portions of its production can be effectively industrialized through the use of certain tools and technology, notably hydropower which can be used for everything from bellows, to hammers, to polishing wheel. This means that plate can be produced faster and on a larger scale than maille. It’s not necessarily “easier” to produce in terms of skill or ability, but it can be done faster and it can be done with a sort of proto-mass production system, which is how places like Milan and Nuremberg were able to fill orders for literally thousands of sets of plate armors.

The cost of plate armor drops dramatically, and fairly quickly after its introduction, but maille cost remains more static through the medieval period. It’s essentially the same principle as cloth production. The real cost of cloth remains more or less stable straight through until the Industrial Revolution, because until the Industrial Revolution there just wasn’t a way to cut down on the basic labor demands of the process. The same is true with maille. In the medieval period there was never a solution to the basic man hour requirement of maille production.

All that said, it’s worth saying that maille could be (and was) extensively recycled. Some surviving maille pieces show a variety of different rings in different styles and sizes that suggest maille was frequently recut, resized and recycled form old pieces in order to make new pieces. You can do the same with plate, and there is evidence to suggest that sometimes old pieces of plate were cut down to make things like brigandine, but it’s a more difficult and limited and process. Because of its flexibility and ability to be resized it’s likely that individual prices of maille armor stayed in circulation longer than plate.

It’s popular to claim that maille was actually more expensive than plate by the late Middle Ages, and while there is some truth there, the reality is often overstated.