You are right. But question who is leading CME or FOREX? When we look at the charts above , quotes of 6E and FOREX the same. I think CME is leading - because it trasparent market and all of participants of FOREX includes the biggest players are trading on CME. It is not a secret that big players use dark pool and transact deal avoiding the market. Why pay commission?
But when they are agree they must have independant point, which price is correct now. Second is hedging of net position. For hedging you need an open liquid market with big volumes. In COT reports you can see all participants of market and their positions. Forex market is repeats CME. But for a lot of customer it is easy to trade with FOREX. Conditions could be better. But FOREX follows CME. The price is the same. But volume is true on CME.