I do not think that it is necessary to match the numbers of the US or exceed them in all categories for the purposes of sufficient defense or counterattack.
I think that the PLAN will soon stop in the number of destroyers and focus more on modernization and replacement of obsolete ships. So, I think that this category will be completed soon.
I agree that PLAN does not necessarily need to match or exceed USN in all counts. However I am not so sure PLAN plans to stop producing more destroyers any time soon. You mention how PLAN is planning on building more carriers so it only makes sense PLAN will produce more destroyers for escorting those carriers. Further there aren't that many obsolete legacy destroyers in PLAN service. Some of them received upgrades in mid 2010s so they aren't going to be retired before 2030 probably.
This batch of destroyer construction alone featured 12 052D. Even if PLAN decided to focus on retiring old ships (Sovremenny, 051B, 051C, 052, 052B for total of 11 destroyers) asap for whatever reason that would only be roughly 1 batch of 052D. Even if you throw in the older 2 052C commissioned in 2004/2005, there's just not a lot of legacy PLAN destroyers to replace. Given the scale of ongoing 052D and 055 construction it seems unlikely we'll see the PLAN destroyer count plateau in the near future.
It's relatively affordable and comes with a decent number of VLS. I'm surprised the PLAN doesn't have an equivalent of the Arleigh Burke, though. They jump straight from 64 with the 052D to 112 with the 055 with no in-between like the AB's 90/96.
052D does seem a little light on VLS compared to many other modern destroyer classes like Zumwalt (80), Sejong the Great (128 or 88), Maya/Atago/Kongo (96/96/90), etc. However PLA VLS is larger and it's not like 64 is majorly inadequate plus 052D has HHQ-10 which most of those do not (they're retrofitting Burkes with an 11 cell launcher for the US equivalent apparently) and so some of those VLS will probably be quad packed RIM-162s which are essentially baseline on 052D.
It could be the case that in a high intensity war having 6 destroyers with 60 VLS is better than 4 destroyers with 90 VLS even though both sets of destroyers have 360 total VLS. It's hard to know but maybe more network nodes and sensors to distribute over a larger area is better as long as those destroyers have at least a reasonable number of VLS. Also there's geographical considerations where for USN which more frequently operates far from their home bases might prefer less warships with more VLS each. PLAN might focus their mission closer to home and not be too concerned about deploying to the other side of the Pacific so might prefer more warships with less VLS each.
All the post-MLU DDGs before the 052C-class that are equipped with VLS cells field HHQ-16s, not HHQ-9s.
Oh thanks for the correction. Still could be useful in second line roles I think. Otherwise I'm not really sure why PLAN would go through the trouble of giving them those upgrades.