First, every priest did not abuse Indulgences, only a few did. Secondly, this has nothing to do with the money changers. The idea behind Jesus chasing out the money changers was that the Gentiles were unable to worship God properly in the Temple, as the money changers were set up in the Courtyard of the Gentiles. With all that commotion going on, how could you expect God-fearing Gentiles to praise God properly? Reverant worship has little to do with abuse of Indulgences.
Regards
Jesus wasn't concerned with a little commotion. It was that the poor and reverent coming to worship at the temple were being cheated, and thus his comment that they had made his father's house into a den of thieves. To buy a bird or animal for sacrifice, one had to exchange his local money for whatever currency was used in Jerusalem. The dishonest money changers were not giving fair value in trade, and the high priest was allowing them to flourish as he received a cut.
In Martin Luther's letter to the Pope asking him to halt the practice of selling "get out of purgatory passes", there is the distinct implication that the Pope allowed it.