For example, for 30k coins at .6% commission:
$30 = $2700 a day
$10 = $1800 a day
$5 = $900 a day.
$1 = $180 a day.
10c = $18 a day
1c = $1.8 a day
Volume hasn't really changed much as prices dropped. So at some point if the prices stagnate long enough it may become uneconomical to run an exchange. And at that point selling accumulated coins won't help much either.
Thats not how an investor works.
Dont think most investors sets out to buy 10.000 coins. They invest x amount of money, its just that they will be getting or selling more Bitcoins.
So the amount of money should be the same.
If Bitcoins go down in value to half, the amount traded should double, otherwise it probably means that people are investing less in bitcoins.
That likely indicates it will go down even more in value.