Long-range SAMs require capable radars such as the 364A AESA, so the 054X you mentioned will by no means be much cheaper than the 052D. I see your point, but if you want to achieve that goal, you may think about building even smaller ships and distribute the systems you need among a larger fleet. The problem is this network may work well for coastal defenses, but PLAN also have to prepare for the scenario China has to project its naval power overseas, which will be inevitable with the Belt & Road initiative in mind.