Its just business...

...or more appropriately, the business life cycle.  I wrote about the trajectory of High Frequency Trading groups years ago.

From a "Frequently Tiresome" publication...

Many high speed trading companies that have reshaped equities trading in recent years are restructuring due to low market volumes and fierce new competition.

Some of the most successful companies of recent years on both sides of the Atlantic are cutting jobs and consolidating technology as they seek out new markets and asset classes, like foreign exchange and fixed-income trading.

The industry upheaval, amid regulatory scrutiny, is a further sign of the impact of the prolonged slump in trading activity on equity markets. Last week it emerged Getco, the US group, was cutting 10 per cent of its workforce.