The answer is simple; The public has been conned! We have been told over and over that price is the most important. Sales bring in customers to buy since the product is now cheaper. Since the price at the lower point now becomes expected, the store finds a manufacturer willing to make the product at a lower cost. This usually means a change in production methods(cheaper components or cheaper labor source) As long as the customer receives the incentive to buy(lower price) everything else follows.
A case in point is cars. Notice that it is now the normal operating mode to offer rebates to drive the sales. If this becomes required then the makers will then be required to adjust costs accordingly.
To quote a famous philosopher " We have met the enemy and it is US"