The cost of these cables is sub-dollar. Like probably less than $0.50. Let's say $0.50 for argument's sake. Bringing the cost down a penny means 2% more sellable product for the same input materials. And when the margins are in the $10 range, that's a huge amount of leverage. They're not passing the $0.01 savings along to their customers. Or even if they are (and say, charge you $0.01 less), it's still a huge differential after you consider the 20x margin.

Quick math:

Let's say 1 million cables at $0.50. That costs you $500k. If you get the cost down to $0.49, you just enabled another 20k cables to be manufactured, and another $200k in profit.