Some would add that, if a (relevant) majority is malicious anyway, no system based on higher authority is going to rein them in anyway.
Perhaps I'm out of line but I don't really think in terms of crypto actors as "malicious" or "benevolent". But more in terms of self interest. If the majority of the computing power involved in a crypto is in it for their best interest (which stands to reason). Then their best interests will line up with protecting the network (vs destroying it).
What we had with BCX was a joker type personality.
The weakness here in my opinion really wasn't that we didn't have enough hashpower but that
1 - The hashpower was centralized at three points of failure. This is the pool problem which even bitcoin hasn't solved. This is a technical issue IMO that still needs to be worked out - litecoin made some strides with P2P (AFAIK this isn't supported in crytponote yet). I'm NOT suggesting this needs to be added. Devs already have too much on their plate. Poor guys.
2 - The financial interest of the pools AFAIK are just the fees they collect from the miners. Which I estimated to not be more than $200ish a day. So really you have $600 a day in incentives as the gatekeepers to protecting a $5 mil market cap. Bitcoin is slightly ahead in this area as the pools have larger incentives (cloud mining, etc).
This opens attack vectors that have nothing to do with how much mining power the coin has. It would probably be more secure with half the hashrate solo mining.
The added attack vectors (that I can think of) are
DDoS the pools
Hack the pools
Bribe the pools
Quietly buy the pools
First remark: interesting discussion. Thanks.
Second: Agreed, but I didn't intend to distinguish "malicious" (or "benevolent") as moral categories.
Inside the economic system of one individual crypto, an actor will be economically irrational if he attacks the network to the point of destruction: he is going to experience a net loss if he destroys the value of the currency that he is paid in. The network value post-attack times his share of the network he gained through the attack must be higher than the cost of the attack for him to consider the attack economically viable.
For an
outside actor, this doesn't hold. He could either have a higher level economic motivation that allows him to take the cost of an attack (e.g. removing a competitor crypto, to strengthen his preferred crypto), or he could be what you called a "joker type personality". I claim that from the practical point of view of the network that needs to be defended, the two are indistinguishable. This is the case I meant by "malicious actors".
The defense against the first type is keeping the total network market value in balance with the cost of an attack. If the former is a lot higher than the latter, a (controlled) attack becomes profitable. "Outside" attacks (joker type attackers, or competitors) can only be deterred by strengthening the network further, to the point where the attack is prohibitively expensive for the attacker
on its own.
I'm pretty sure the Monero network is far from the second type of security yet (the Bitcoin network might be close to it, for anyone other than a government organization or extremely large company), but I suppose your point could be rephrased as that the network isn't even secure in the first sense so far.