Crystal structure prediction by itself is a very hard problem. Just given the chemical formula and asking "what is the most stable structure" is a global optimization problem. And this is just for one single composition. It isn't an easy global optimization problem either. You not only have to determine the unit cell vectors, the positions of the atoms in the unit cell, but also the number of atoms in the unit cell needed to represent the structure! Just because you are even given "Pb9Cu(PO4)6O" as the formula finding the most stable structure, let alone the superconducting non-minimum energy state is a huge undertaking. Now expand that to all of chemical space and you can see that it is not that easy!

Edit: Also look at how long these (short pre-print) DFT articles are. These aren't simple calculations to interpret.