As far as i knew & saw in China, China was experiencing the Science Revolution. New Technology & New Equipment Invention, first Ten~Twenty years of 21 century it's a Great Golden Time for China development. There's World N.o2 economy support R&D and ships building, PLAN's A.C Fleet project.
For PLAN, 052D (60x vls) as the air-defence guard of A.C Fleet, 055 (100+ vls) not only the fleet guard also can execute Ocean Task leaving A.C Fleet. Compared ship cost, 055 also more expensive than 052D.
Future PLAN strategy 052D & 055 DDG has different task function, that's the reason why CSSC building 052D & 055 together.
At the same time, China was developing new technology in some small boats first, when it's mature CSSC will build new DDG with new mature & reliable technology.
1. China Triple-hulled Vessel design
2. CCG 3,000ton (The full integrated electric propulsion, IFEP) full electric power system ship
Above mature technology will used in future PLAN new DDGs ↑ There will be 052E & 055A etc...