My "test of water" starting from some STATEMENT of facts, which didn't mention above, yet.
1. Han dynasty, when roughly equals Rome republic and early Rome Empire: Rome's goal is to conquer other non-advanced nations (if not races); Han's goal is to PRESEVE the potential to (still) be a centre kindom when the Qin dynasty before it has reduced 3/4 of the nation's population and ruined ALL (I am not using "almost") of the nation's infrastructure, and nomadic tribes and kindoms (Hun is one of many) from north, west, northwest, southwest... trying to "make some easy money", as frequent as like twice a year...
2. Although many big or small, long or short, loved or hated dynasty after Han and before Tang (Sui, actually), but we can use simpler term as "there's MORE splited and warlord-divided times than peaceful, infrustructure building times.", plus foreign (mostly, nomads) invasions trying to "make easy money", or even to "usurp" the middle kingdom, at her weakest, everytime.
3. Symbolic Tang dynasty, if there is something that can (foreseenablly) threaten the early till middle years of Tang empire, they are the unhappy kingdoms (not nomads, although barbaric) that at north, west, northwest, southwest of door-steps of Tang. Not to mention started form middile years of Tang, THE greatest rebellion throughout China's history, of auxillary forces rebel against imperial forces, minority-races (naturalisation citizens) rebel against majority-races hans (born citizens), that historians generally and simplified called " An Shi Zhi Luan" 安史之乱 - that this kind of social plague rooted form border area of the nation.
4. Song dynasty, simple term - under the thumb of "converging attack / threat" of numerous ethnic-unified, Chinese culture influenced, kingdoms (may or may not be nomads, but somewhat civilized-infrustructured kingdoms), tribes, even self-claim empires, form north, west, northwest, south, southwest.
5. Yuan dynasty, some (including me) consider them - usurper of middle kingdom, (if consider threated), faces threats at north and west. - To east, not yet threatened.
6. Ming dynasty, although drived the mongols back, threatened from north, west, north west... and somewhat threatend form east, and they dealing the easten threat with shut down the sea, effectively.
7. Qing dynasty, some (including me) consider it a very successful, even admirable - usuurper of middle kingdom, untill defeated by British, threatened from north, west, north west... and ignored the threat from east by shut down the sea, not effectively.
What points I am making here, is that: Gentlemen, ancient China, from philosophy to stratege, from national infrustructure to common people's life style... was designed, prepared, meant, to deal with threat from north, west, northwest, south, southwest - if not within - from the land / ground.
It is like Maginot line, you can't say it is weak or inferior. It's just it didn't EFFECT, when time comes. Defining "technology superioity" by wins or lost, by gains or wastes, by GDP or gold stock... it is unpractical.