You start something with the easy things, next iterations with more complicated ones.
There's no economy for now (and the ships if someone want to test them are already reachable with REC), clothes for personalization, weapons, armor sets, maybe then ships components and the ships. Until they put the ships ingame there's no cry for the price, and right now there's no progression, there's no reason to put it in the first iteration.
Start with the basics, then you just need to build on that. Right now the Alpha doesn't need the ability to buy a ship(IMO), need that if a get a gun I can keep it, if I do a mission I dont have to do it again if I log out the next hour, better party systems, among other multiple things. Even before getting to the point of selling the ships ingame I would expect to have at least the basics missions with cargo and maybe mining(with this is perfectly reasonable to let people buy mining ships ingame).
They will let everyone buy ships in the alpha eventually, just not(I don't believe it at least) in the first iteration.
But as always this is just my opinión about the subject, everyone can believe whatever he wants.