What you forget is that those RPs have to come from somewhere in the first place. People can't accumulate RPs out of thin air. There was also the EM tax to help sink RPs out of the system.Doubtful they will reintroduce the exchange market, people didn't need to spend money on RPs because of it. Everyone was also selling items for ridiculous prices, for example 2x upgrade weapons were going for 20k-50k RPs which equates to 200$-500$. It got to the point only those willing or capable of spending 1/4 to 2/4 of their paychecks were playing anymore.
But that's exactly what was happening, it had got to a point that the same RPs were just circling the exchange, one person would drop 1000$ on RPs and purchase multiple items that would just cycle back to a single person who would then purchase a large expensive item that would then cycle through buying smaller items that would eventually make their way back to a single person and the cycle would continue.