The runs are limited, but on the other hand, all the hard work in producing those models, such as research, development, castings and so on has been done, which means that further runs of any given model can be produced in the future with little effort if the market demands it. In fact, extra runs of the 141's have already happened. A couple of model shops commissioned a batch of 171 after MM had released all that were planned, and then a further batch of 141 was produced after that loco was preserved...