essentially yes the exchanges have reps that visit the larger volume players. The exchanges have market maker program that the firm can join. In return they get extremely low round trip cost and/or rebates. The competition is huge for the most liquid products however there are plenty of opportunities for smaller players in less liquid properties and 'rival' products. A rival product is where an exchange is trying to take volume from the most liquid contract. For example Brent on CME has a rival product for ICE Brent and vice versa.
As well as the market making in the traditional sense there are also other strategies which providing liquidity. So for example I might wait for a certain condition to be present and only then look to provide liquidity.