This is the sort of thing that economies of scale bring when paired with a lack of effective competition. If there's effective competition, then some company can and will cut into all the other companies' sales by selling a fully-unlocked version of their hardware at close to the price of the locked version.
Economies of scale by themselves cause lack of effective competition, because the biggest company automatically wins by taking advantage of the economies of scale and the rest go out of business. That's why an industry with significant economies of scale is called a "natural monopoly".
