As a result their business grew quickly and the other stores were unable to compete and went out of business. Then with the market to themselves they raised their prices to increase their margins. They also used access to adjacent markets (TVs, PCs, Radios, Appliances, Office Supplies) to supplement their margin which specialty retailers like Quement or Jade did not.
Their strategy was essentially to lose money on something that brought in customers, and to make extra money on other things once the customer had been acquired and was in the store.
The "grow fast at any cost" mentality is predicated on the understanding that the most difficult step of any new business is to change consumer behavior such that they go to the new business first. Once they have established that pattern they can then manipulate the pricing of their offerings in order to achieve the highest sustainable level of margin before they lose customers.