How much security do we really need? The hash rate is a measure of security, but it is so exorbitantly high that no single individual will come close to it attacking it.
If half the miners dropped out, like they just did to go mine BCH, would that be such a bad thing? Difficulty will readjust, BTC will still hum along. Eventually the only thing that will make BTC profitable will be if enough people adopt it and transaction fees pay the difference in electrical costs since block rewards will drop off.
Am I missing something? Of course we want security, but I really don't think we need this much. From my perspective, we are in the mining bubble stage. Unless hash rate drops so low that it could be attacked, there shouldn't be a real need to worry.
So, why don't you tell us how low the hashrate should be to keep Bitcoin's blockchain sufficiently secure?
No-one can answer that question definitively, Satoshi's cryptocurrency concept isn't sufficiently mature to make such non-empirical judgements. If you've actually got a meaningful, empirical way of analysing the issue, please tell us. Until then, the hashrate will simply follow the price, and self-interest will drive miners to compete as efficiently as they can (and hashrate security will continue to be a by-product of that).
I mean, what's the actual idea being proposed by the "hashrate is too high" contingent? Anything?