It appears the hashrate has gone up since the halving. The mempool seems to be below 1M ATM too. Looks like all the Chinese mining farms brought more rigs online to compensate for the loss of income. Could just be luck, but I doubt it.
The pie shrank, but everyones share remains the same. Adding more miners to compensate for lost income across the board, that makes little sense...
It makes sense if you build your farms near a hydroelectric plant in the cool alpine regions of Tibet. The electricity is very cheap and the climate is cool. Also, the difficulty doesn't increase for a little over 1180 blocks at the moment. The block times since the halving are quite a bit shorter on average. Antpool definitely turned on some machines. They mined over 40 blocks in the past 24 hours and they usually only mine somewhere in the 20s.
So you're saying people had miners sitting idle when rewards were 25BTC per block but turned them on when they fell to 12.5BTC? Not at all logical.