2000 sets a year of what, do they count each individual module, or 2000 sets of everything described, for 2000 potential conversions? If former it's still a remarkable figure (few hundred potential conversions per year), if latter that's astonishing if it means 2000 armed merchants per year. They could literally drown an enemy just with armed merchants alone, it doesn't matter if the exchange ratio is 10 merchants to 1 enemy warship, China can build several tens of millions of shipping per year. This is of course a very simplistic appraisal and the human factor must be considered (crews for all these merchants) but i guess the next step is to make them unmanned or at least minimally manned?
As of now, there are about 7500 seagoing container ships worldwide. I don't quite see how China can fully arm them all within 4 years. So of course, the article meant 2000 individual containerized modules per year.
In retrospect, per our observation so far, a container ship with the capacity of Zhong Da 79 can carry about 21 containers in fully-deployed mode (i.e. containerized VLS erected, radar, sensor and communications systems operational, CIWS and decoy systems functional). Of course, this doesn't yet include any potential containerized power packs and/or generators + fuel storage to supply power to the aforementioned systems, alongside containerized command and support systems that would mostly be stacked beneath the top container rows.
Hypothetically speaking, 2000 container modules a year would mean ~95x Zhong Da 79-worth of armed container ships per year, which is certainly way more than the actually feasible number of container ships that can actually be fitted with such systems per year (when taking all the aforementioned extra modules and larger container ship sizes into account).