Does anyone know why futures products (for the most part) only trade on one exchange? Don't get me wrong, I think there are definitely a lot of pros to this more simple structure, but think there are some cons as well.
I think because it's not really a product. A stock is something you own... whether you trade it on exchange A or B or C... the stock stays the same... with the same voting power etc. Futures and other derivatives are just agreements based on certain specifications, as set by the exchange. You have far less rights with futures and options. I don't know whether it works this way in the US, but for instance in the Netherlands... if you hold options or other derivatives and your broker or bank goes bankrupt... you have no legal position in getting back those funds. So I think it's a total loss of premium. While stocks/bonds are held by your broker/bank as a custodian... you will always keep the rights to those stocks, they are yours. So, maybe it's because of the way the contracts are treated in a ownership kinda way? Although... if I buy options through smart routing and they spread across several exchanges... if I trade out of it, they don't have to be traded on the same exchanges as I bought them... So why wouldn't that work similar for futures... hmm....
To your point about options routing, there are 15 equity options exchanges in the U.S. and most equity options trade on all 15. When Reg-NMS came around (early 2000s) options exchanges are obligated to route or manage your order to the away best price. Prior to that each option exchange had their own list of products that were only traded on their venue. There are the big proprietary products SPX/VIX that only trade on the CBOE but I can't see how a commodity future could be proprietary to one exchange.
Almost all futures contracts in the US are single list. Some CME stuff used to trade SGX. This is really about the virtual monopoly in clearing the CFTC allows. Some of the old NYMEX (now part of CME) energy contracts have virtually similar contracts trading elsewhere, but they are not fungible.
FYI, In the Netherlands (and probably many other EU states), derivatives are protected up to €20k under the so-called BCS (Beleggerscompensatiestelsel - More info: http://www.toezicht.dnb.nl/2/50-202210.jsp)