Just for the record, it states on their web site (shown in the original post in this thread) that these plates are manufactured using a 3D Printing technology, so they are not injection molded.
But that said, the $100 price is no more of a rip off than anything else in this hobby. Hi End audio products are generally not priced based on the cost of production, but rather based on what the manufacturer thinks will be the perceived value to the customer of the improvement they get to their system. Do you really think that the costs of the parts and assembly of a $32k DAC justifies that price? Of course not, they price it at $32k because they think there are enough audiophiles out there that will think it provides $32k worth of performance. This case is no different. If enough people think that it is worth $100 to keep their power cords from pulling out or away from the plugs, then they will sell a lot of them and be able to maintain that price. If it does not sell well at $100 the company will have top decide if it is worth lowering the price to make more sales or should they just kill the product. That is just simple supply and demand economics. Any rational business will sell their product at the highest price they can get without deminishing total profits.