The fact that the nail scissors are three times more expensive is a superficial consideration.
Here you would at least have to compare scissors of the same quality or, better yet, from the same manufacturer. Someone who makes left-handed baby nail scissors produces smaller quantities. Consequently, the cost of the tools to make these scissors is spread over the smaller quantity. This only makes them seem more expensive when compared to products from manufacturers that only produce right-handed products in large quantities.
Right-handed baby scissors cost the same or even more if you pay attention to quality. The baby nail scissors from Zwilling, for example, cost EUR 24.95.