I basically agree with what you're saying, but I think there's another point to make - market making is simply not as profitable as it once was.

I've seen estimates that the entire high frequency trading industry made $1 billion profit in 2013, down from $5 billion in 2009. [0]

In contrast, JPMorgan made $6 billion profit in the last quarter, and that was reported as "not particularly impressive"! [1]

[0] http://www.reuters.com/article/2014/04/06/us-dark-markets-an...

[1] http://dealbook.nytimes.com/2014/07/15/jpmorgan-earnings-dec...