I think the appearance of this "055" mock up lends credence to my theory that China will only build 6x 052Ds over in the 052 thread. Even though the length of the mock up is difficult to ascertain, estimates do bracket the length of the 052D. The 052D is one generation behind the world's latest destroyer designs while this mock up aspires to be one of them with the integrated mast and such. Also, if as someone else posted, the lead time from mock up to launch is around 3 years then why would China load up on more already somewhat outdated 052Ds when this up-to-date design will shortly be available.
Sigh.
First of all, 052D is not "one generation behind" the world's largest destroyer designs. Generations are typically defined by the technology of the ship,not the size. In that sense, 052D is in some ways half a generation ahead than the ships you are talking about like burke, atago, sejong or ticos, given it uses a next generation APAR and a more modern and more flexible VLS.
As to why the PLAN will build more than 6 052Ds — retirement and fleet planning. The PLAN will continue retiring some of its older destroyers like 051 and they will need ships to replace them without too much delay. More importantly, if they do cease 052D production at 6, they will be drastically cutting down their short to medium term capability because putting it plainly and simply: they are losing out on six damned good destroyers, which may not meet their ship number requirement.
You do not continue or cease to build ships solely on how advanced they are, you build them because of the capabilities you need which is dependent on both the qualitative capability of the ship and the quantitative number of the ships you have. So saying that the PLAN can build 6 052Ds because they have 055s coming up based on how technologically advanced they are is not a logical argument