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? Heck, it'd be awesome if it would, our coins would be worth tens of thousands of dollars (maybe hundreds of thousands) and we could sell them to the fools, then turn around and start a new coin, abandon the old one to the malicious entities and all be SUPER rich on top of it all.
The trolls don't think this through.
Where he gets the idea that this situation is limited in time is beyond me. The more time goes on, the more distribution of the masternodes we get. More different people buy them, the holders of tons of MNs sell a few, and others buy, etc.... On an open and free market. It's just not possible. And it gets more impossible each day.
This does not rely on honesty, this relies on the self interests of all parties.