The problem is, we don't know where they are on game mechanics development. Like cargo. It's not just the ability to have cargo magically appear in your hold. It need some way for other parties to steal it. That means that the cargo needs to be a separate entity from your ship and not just a numeric value that changes when you click buy or sell. It also needs to have weight. That needs to be balanced with ship engines and the game physics. But then, different cargoes need different weights depending on how much of what they are. Then you need a way to manipulate it and move it around, store it, etc. You need ways to lock ships and break into them. You need permissions and character identities. Every one thing leads to a cascade of other things that need to be created with it. We have no idea how much of this is already complete if any.
So with mining, they would cargo first. Because the mining results would be cargo. It needs to have all the same flexibility as any other cargo. Then, it needs to come from some place either planet or asteroid. Then it needs to be finite. When you mine out an asteroid, it needs to have a depleting ore value in it. Then they need to have buyers and sellers, a way to move it, values for each type and a place to bring it.
I mean, sure. We can fly around our ships. We can sit our avatar in a chair and control the features of that ship. We can run around and shoot things. But that is literally just the tip of the iceberg. Those are the easy implementations in cryengine. Those basic functions are pretty much built into the engine. What we lack in the PU, is everything else. We're missing all the custom work that they are building and we see tidbits of now and again. It scares me how much of this game needs to be built from scratch on the back end.
I hope they are much further along than they are telling us. I would imagine they are, but there is no telling just how far. I know that the things we can see and play around with now are just the skin, the easy things on the surface. The background mechanics of this thing though are what are going to make the difference. Unfortunately, it's the thing they are most secretive about.
So could it show up in 3.0? Absolutely. We do know they are working on everything simultaneously with different studios and groups within them. So it is easily feasible that the mining team is just as close to their finish line as the cargo team. The uncertainty of it all drives me nuts really. It could all fall together and we may have a full beta next year. Or, it could drag on for another decade. It all depends on how far along they are with the background systems that they never talk about.
EDIT: I may have rambled a bit there...
"Mr. Madison, what you've just said is one of the most insanely idiotic things I have ever heard. At no point in your rambling, incoherent response were you even close to anything that could be considered a rational thought. Everyone in this room is now dumber for having listened to it. I award you no points, and may God have mercy on your soul"