Japanese stiltgrass has one minor weakness: it grows so prolifically that it chokes itself out with big thick mats of stilgrass straw.  Many of the weeds in your proposed list can compete with stiltgrass by growing through and above it.  Many like autumn olive adapt to dry areas and thus do better in dry years than stiltgrass.  Stiltgrass's preference for moisture is a very minor weakness slowing it down in dry years.

Other than some competition, there are no natural barriers to stiltgrass.  It simply takes over gardens and wild areas and stays endemic and can become prolific in mowed lawns.  In riparian areas it can use its length to smother anything other than mature trees and shrubs.