Blizzard did not see a "need" to address. They saw that people were actually willing to shell out real money for make-believe items and created a game to take advantage of that idea. They created a game that was designed around an auction house, rather than designing a good game where people would choose to use the auction house if they wanted to (you know, like the people chose to use the shady sites to buy items). Now instead of it being a choice, they made design decisions to funnel all players into making it more likely they will use this "feature". By making it online only. By neutering chat channels. By screwing with drop rates. By making progression item based rather than skill based. All of these decisions are made to enhance the likelyhood that you will use the auction house, thereby giving them money.