The merchant marine can also be a good source of recruitment, especially when economic times are hard for the shipping business. Plus you already have a ready base of people who already have sea legs, knows how to live inside a ship, and some basic experience in operating a ship, as well as an understanding of working under a strict command structure.
Globally, the merchant marine is populated dominantly by nationalities whose people seeks to escape poverty.
Now as for the PLAN having manning issues, and why have those Type 052D haven't been commissioned yet, I also have a number of theories.
1. They stopped posting and covering commissioning news. Maybe they want to make the PLAN look less aggressive or imperialistic. However, we can see if a ship is truly operational or not once they have completely moved out of the shipyard and into a PLAN base. Does it appear that some of the new 052Ds have gained pennants recently?
2. Commissioning of the 052Ds suddenly has taken lower priority, because you decided to suck the crews out and deploy them somewhere else. What ships could suck this up? The new carrier for example. Or the Type 055. Or both. You also have two Type 071 LPDs.
3. PLAN may also have been prioritizing Type 056s as a crucial part of its Great Wall of the Sea. This can explain why such a huge number is built in a few years. Not just for a sovereignty picket line ship, but also to use the seas as a bastion for its ballistic missile submarines. Its similar to the Soviet bastion strategy, which frigates like the Krivak and the Riga class played an important component.
It should be noted, that the Rigas in turn, starting with the first few kits that were delivered to China, were among the first ships of the PLAN, as Type 01. Reversed engineered, this started a long evolutionary line of ships that led to the Jianghus and Jiangweis, and which the Type 056 is finally their successor. The Type 056 is modernizing, for what has been, the main part of the traditional brown water PLAN that were filled and modeled after what the Soviets refer to as a "guard" ship.
The Krivak class frigates? The corresponding match to that would be the Type 054A frigates, which also again, is high priority.
This really isn't to say that the 052Ds are less important, but maybe they can get 054As and 056s faster into the water for the short term, then eventually commission in more 052Ds.
As for the employment strategy, I also believe in that, that naval shipbuilding is and always has been about jobs --- its been demonstrated continually with other nations as well. But in this case, China has over 1600 shipyards, and only a very small number are certified to do warships. Naval shipbuilding as an employment strategy is like that Dutch boy trying to plug leaks in the dam with his hand. Sooner or later you have to consolidate and pick winners, and allow the rest to rest.
China's shipbuilding are consolidated into two large mother companies, CSSC and CSIC. CSSC handles the south side, CSIC the north side. CSSC handles the Type 052 series destroyer, the LPDs, the LSCs, the frigates and the corvettes. CSIC the Type 051 series destroyer, the carriers and the submarines. At some point they decided to share the Type 052D (Type 052C was CSSC), so Dalian can build the Type 052D while putting the Type 051 series to rest, and combine their resources for the Type 055. In exchange CSSC will start building submarines too, starting with Yuans at Jiangnan.
So basically, Jiangnan, Huangpu, and Hudong are CSSC, while Dalian, Huludao and Wuhu are CSIC.
Larger and more complex warships --- destroyers, carriers, submarines --- will benefit only the largest and most technologically advanced of the shipyards.
As an employment strategy you need something to make better use of the smaller shipyards, and that's where the corvette and frigate building comes in. One has to make full use of all capacities, both large and small shipyards.
