You do have a point here. Only, I do not really think tanks like 96A are simply 'numbers fillers'. The 96 family is indeed an ‘economic’ choice, but even if we put that aside , given the diversity of terrains in China, they still do have a reasonable demand for 40~50 ton MBTs.
You are missing half the picture again.
China do have plenty of requirements for 40-50 ton MBT but that DOESN'T mean it has to be a "compromised" MBT. Compromised in comparison to top tier 40-50 ton MBTs like Type 10 but the 96 is the right tank for PLA as it is. Would PLA rather have 3500 Type 96 in total over the years or would it rather have 1200 Type 10 level light weight MBTs?
I insist to you all that there is absolutely nothing challenging about developing a 1200hp engine that is as reliable and long lasting as they come from Germany. This is a science, not an adventure in racism. This shit is so easy that a grad in material science can form the basics to do this.
The industrial ability to do this in China has been around since the 1990s. The processes and theories have been there even longer. There is only details in implementation and the differences in procedural and operating standards that would set apart a novice with all the right knowledge and tools (but not the experience) and the experienced pro that's done it for decades. That and of course minor details and technology improvements that I'm sure are higher level industrial and proprietary secrets which I am not including in that assessment. Suffice to say, China could build a super engine if it wanted or needed to. It just simply doesn't because it needs a lot of very cheap tanks it can build, maintain, make parts for, and repair very quickly and cheaply.
The
choice to have "compromised" (relative to highest performers) performance and requirements comes from military doctrine.
This isn't just armour distribution and engine but on the 96A even very evident in equipment. The 96A uses some very obsolete equipment and that's because it's so expensive to equip all of them with the latest night vision, thermal cameras, barrel reference sensors, laser rangefingers, optics and so on. The opportunity cost for the PLA in terms of monetary and fighting capability is simply not worth it. For that time, material, and money, they can much better spend it on developing and fielding top tier weapons like HGVs, electronic attack systems, new cruise missiles, stealth bombers and so on. Sure the measly sum of a thermal camera isn't going to cover that but it is a management of resources and allocating them efficiently.
PLA knows it doesn't want to fight
those kinds of wars that require their MBT to be equal performance to the adversary. It also needs more numbers. Hence 96 is in many ways a numbers filler just by virtue of being PLA's backbone MBT which has to be positioned all around China.
It isn't just an economic choice but as much a military one which I keep explaining and emphasising. It
is a compromised tank intentionally not given the best and latest or allowed its designers and builders to use the most time, money, and material consuming designs and processes. This is an engineering problem at that level where the developers and builders need to satisfy a list of requirements for a cost. Same reason a $10K Indian made car is not going to be comparable to a $100K German one. It isn't designed to be nor does it fill the same role and purpose!
96 is a shabby tank no matter how one assesses it but it is a tank and it brings a 125mm with all those rounds to a fight. The important, big brain question is how you engage and shape the fight. Thinking about that reveals why PLA uses those specific war fighting doctrines. Then remember that 96 lineage and the condition of China's heavy industry from the 1970s to 1990s.
Personally I think this generation of tanks is being stretched so much longer because tanks are becoming increasingly invalid. They definitely will continue to hold an important role but that role is eroding and the remnants of it are so low in requirement that most top tier militaries have barely made effort in even upgrading MBTs, let alone redesigning and introducing a new generation of them. Russia's an outlier in this because they anticipated (well it was obvious from 20 years back) tensions that require armoured warfare to be in top shape.
PLA's aim is to gain and hold air, space, information, cyber, and electronic superiority. By way of which firepower can be delivered more effectively and efficiently. By way of which superior positions and strategic maneuvers and actions can be gained and made with minimal costs. By way of which tactical advantages can be manipulated out of even using inferior tanks for example. A massive horde of Type 96A with very little side armour and lower longevity engines is going to be FAR superior to a few super Leopard 2A7 that has all its supports knocked out, blinded, and dead.
A military of arbitrary number of soldiers and 100K *insert preferred NATO tank* is not going to have a chance against a military with hundreds of gunships and drones and 100K crappy MBTs. Crappy MBTs with all variables equal mean some more important domain have better capabilities. PLA not giving tanks much funding speak volumes about what they think of warfare.