IMO you are right on that, however this is a failure of all cryptocurrencies, not DASH exclusively. Cryptocurrencies rely on attacker economist rationale, including Monero, Bitcoin etc. "Honest miners", bloat attacks vs fees increase (Bytecoin attackers (?) on Monero), etc etc.
Actually, AlexGR, he isn't at all right. Mostly because he presents one attack vector, which is nearly impossible to acheive, as the only issue. The point isn't to get a majority control over all masternodes, but rather a 90%+ minimum for less than 1%
chance of deanonymizing a transaction.
It's not a matter of how much it costs to gain control over the MN network enough to either deanonymize a transaction or other malicious actions (such as double spends, etc...) It's a matter of ability, and there is no way any entity can do this without just about everyone selling off their Masternodes, and only to this malicious entity in a free market. You think that's going to happen?
The nature of the dis-incentive is of the type he originally described. In other words, a rival with tremendous amount of money can theoretically attack the system. We are counting that this is not "realistic" to happen.
But the same is true for all cryptocurrencies (PoW, PoS) and their entire operation.
The same is also true for all mixing-based anonymity systems, due to the possibility of sybil attacks.
What are Monero guys saying against Bytecoin? "Ohhh the preminers hold 80something % of the first coins which can be used to deanonymize the mixin of later users..."...
Now, of course, there are degrees of chance, probabilities, etc etc on what might happen. But, in the end of the day, even a 0.000000000000000001% chance that something might go wrong, is proof that the system is not designed to be 100% robust in itself, instead if operates with certain assumptions on the economical behavior of the users of the network.
Somewhat agree. However, what you are missing from djb's point is that these sorts of arguments can be very fragile. The cost of attacking
a transaction by spending a lot of money may be very
small large and therefore not feasible. But if you can spend the same "a lot of money" and in doing so attack
many transactions, perhaps in a clever way that no one previously thought of, the cost may then become feasible. This applies to other cryptocurrencies in various ways, yes, but we are discussing Dash here.
I've argued before that there is really
no cost to attacking masternodes (it is a variation of the nothing-at-stake attack that bedevils all PoS systems, which is what masternodes are). You don't have to buy them all up right now, fighting liquidity all the way up. You can slowly accumulate over time since your return-on-investment is
higher if you are an attacker with ulterior motives (you still get the same rewards everyone else gets, so financially you are on equal footing). So you can always afford to pay
slightly more for masternodes and accumulate a majority or all of them over time, while others find their ROI
slightly lagging and over time drop out. In effect, the structure dictates a race to the bottom.
EDIT: typo small -> large