@377.... it's a logical theory, but a couple points.
fix can do at least 2k orders/sec. my last executing broker with a very inefficient implementation could push 1k per second no problem.
real hft firms though aren't using fix. they're writing directly to the exchange specific api's. arcadirect can handle 5k/sec with acks in the microseconds. other exchanges are as, if not more, competitive.
as far as your comment on the patterns being out of market tests... look at those charts again. most of those are happening on the nbbo. and ALL of them are happening on the particular exchanges bbo.