Exchange price for a key is usually in the 1.2-1.4M mark. So they'd have AT MOST 45M ec to spend. Never mind "get any of the lockbox ships other than the bug ship", I don't think there is one lockbox ship you can buy for 45M ec, excluding Mirror vessels and the Tuffli (which isn't technically a lockbox ship anyway).
I do agree with the sentiment that buying Z-store stuff to resell is the most cost-effective way to get a lockbox ship on average, but you'll need considerably more than 30 to get anything worthwhile (unless you have very good timing and pick up an "oops, missed a zero" bargain ).
I bought 2 Temporal sci vessels a week ago for $40 million each. They were $100 million when the boxes came out same as Recluse carrier - but if you wait a month or 2 they usuall drop in price by half.
One thing I haven't seen anybody bring up is that the other stuff that comes out of the boxes itself has EC value. Doffs, even white/green ones, in aggregate add up to a lot of EC. In fact, one of the games to make EC is to get the Doff minipacks that people don't open from the Exchange, open them, then flip the Doffs that come out for profit. Some regular Doffs are worth a decent amount of EC, especially if you get one blue or purple. Certain special Doffs like the attack pattern ones are worth a lot on their own. Even the skill point bonuses are worth something.
So, even if you don't get what you want out of the boxes, if you sell off whatever you do get and put the money aside, eventually you will have enough to get your ship. How much it'll cost you in Zen, I'm not sure, but there are numerous other ways to get EC. And, who knows, part way along you might get lucky...
Thing is its a lottery - a gamble - and you are guareeteed to get something. If someone buys $35 dollars in lottery tickets and don't win the grand prize or there $35 dollars back - almost all people just say - ah well - maybe next time and rip up the tickets.
I've stopped buying zen save by converting earned dill to zen, since in 80-100 keys used, I only lucked out once and got a orb weaver. In game, I ground up the dill to zen for a Armitage, Atrox, and sold everything viable I had over a SEVEN MONTH period to finally earn myself a Dkora. Too bad there's no way that you could get keys/boxes that can specifically only be bought with IRL cash for zen that would say give you a higher chance. Maybe then you could argue it'd be PTW, but hell, at least we'd know our actual spent money gave us a higher chance. And also, if you wanna talk about non-starfleet ships being rare, try parking outside of ESD. I lost count at around 20 non-Starfleet ships by it.