I fear it's a result of exchanges condoning the imo disgraceful behaviour that's been commonplace the last 6-7 years.
By allowing these giant alleged mm's to pretty much do as they please despite numerous wanings from locals they are in a position now where if a big fund or broker goes down the market is severely impacted.
Makes a good case for having lots and lots of smaller players indirectly market making,picking up the slack as and when needs be as opposed to 2 or 3 giants.
Say for instance that RSJ suddenly went out of business,what would happen then.
( I use RSJ as an example here as I read somewhere that do a huge amount of volume at liffe,something ridiculous like 40%)