For those who are not reading the list, here a part of Lukejr's mail:
Quote
We are coming up on the subsidy halving this July, and there have been some
concerns raised that a non-trivial number of miners could potentially drop off
the network. This would result in a significantly longer block interval, which
also means a higher per-block transaction volume, which could cause the block
size limit to legitimately be hit much sooner than expected. Furthermore, due
to difficulty adjustment being measured exclusively in blocks, the time until
it adjusts to compensate would be prolonged.
For example, if 50% of miners dropped off the network, blocks would be every
20 minutes on average and contain double the transactions they presently do.
Even double would be approximately 850-900k, which potentially bumps up
against the hard limit when empty blocks are taken into consideration. This
situation would continue for a full month if no changes are made. If more
miners drop off the network, most of this becomes linearly worse, but due to
hitting the block size limit, the backlog would grow indefinitely until the
adjustment occurs.
concerns raised that a non-trivial number of miners could potentially drop off
the network. This would result in a significantly longer block interval, which
also means a higher per-block transaction volume, which could cause the block
size limit to legitimately be hit much sooner than expected. Furthermore, due
to difficulty adjustment being measured exclusively in blocks, the time until
it adjusts to compensate would be prolonged.
For example, if 50% of miners dropped off the network, blocks would be every
20 minutes on average and contain double the transactions they presently do.
Even double would be approximately 850-900k, which potentially bumps up
against the hard limit when empty blocks are taken into consideration. This
situation would continue for a full month if no changes are made. If more
miners drop off the network, most of this becomes linearly worse, but due to
hitting the block size limit, the backlog would grow indefinitely until the
adjustment occurs.
Basically Lukejr concern is when halving occur and blocks become worth 12.5 BTC instead of 25 BTC, half of the hashrate might shut down to keep the same profitability. But because block will be created in 20 minutes on average instead of 10 minutes, even half of the hashrate shut down will not save miners profitability because they will receive only half of the bitcoins to stay profitable (20 minutes to generate Bitcoins instead of 10 minutes). If miners shut down another half of the hashrate, the block time generation becomes 40 minutes on average but they will receive only half of the bitcoins to be profitable again, also know as doom down spiral until difficulty readjust after one month.
I know it is just simple example and in real world minners have differently effective miners so the most effective miners can stay profitable while the old miners might be turned down. But Lukejr got a point.
So halving is definitively not a sure way to get the price up, at least short term.
