I don't think they have even started buying. The blocksize "war" has actually slowed down the growth in confidence...
This. And the fact that the halving will not influence the final price by a lot as there is no reason for it to happen.
Unless miners dumped say 50% of mined coins daily and will continue doing that after halving, which means 25% of current supply, than it might be notible that there are less coins on the sell orderbook. But I doubt this is how the miners sell their coins anyway.