You may be right but it's a pretty common business strategy to get by on very low markup on the principal commodity and make money on the peripherals.
Kodak did it with cameras, selling them cheap and making money on the film and processing. Car dealers will take a tiny profit on the car if necessary and then sell wildly overpriced add-ons like undercoating and extended warranties, not to mention the finance and regular service charges. You can get an ink-jet printer for practically nothing because the manufacturer knows you'll be back within a couple of months for ink cartridges that cost more than the 'retail' price of the printer.
At least with cables it's up to you whether the markup is worth it to you or not.
