It really all comes down to the materials and construction methods. Saddles with carbon fiber rails, bases, and 3D-printed tops are expensive to produce and therefore cost more than models made with less exotic materials and simpler constructions.
Like many things in cycling, spending more also equates to a reduction in weight which may be important to many riders and racers. Assuming you’re okay with carting around 100-150 extra grams, there are plenty of comfortable saddles that are a fraction of the price of the top-of-the-line models.