Contradiction to mechanism design in economics

Mechanism design is one facet of game theory which creeps up in multi-agent systems literature when complex decisions have to be taken. The 2007 Economics Nobel prize was awarded on the same theory being proposed to introduce efficent market algortihms.
In theory, mechanism design relates to the making of decision by every agent keeping in consideration what the other agents might decide, not only to maximise its own utility factor but also the system's overall performance. And this is why most MD literature refers to auction based mechanisms where every agent submits their bids, and a central agent decides who gets to perform the task. There is much research progressing towards how this could be applied on a decentralised manner to acheive the same goals.
However, in reality if we were to apply this principle to for say, malls competing for the same pool of customers, every mall agent would be wanting to increase their own profits, possibly predicting the other mall's behaviour before making the decision, giving less consideration what would be better for the complete society. This is possible why the proverb, rich get richer and poor get poorer might be true. every agent behaves only on their preferences, not caring how the community gets affected. And this is why some businesses might be able to monopolise the business by various strategies taken at the right time while others only struggle to survive.