I think it is the other way around. The so-called "Chinese martial arts" are plays made by street artists for food, they were never real techniques used by any Chinese military in the past. What the military used was and is always something practical and Sanda is just a morden name. PLA just continued using it.That is why Sanda is adopted by the PLA and police force instead of any of the traditional Chinese martial arts. It is a much more practical and grounded martial art. Sanda is derived from a combination traditional Chinese martial arts, so it still is a Chinese cultural heritage. Seeing it work in UFC is further vindication that the Chinese have successfully modernized their martial arts for modern circumstances. And that the PLA knows what they're doing.
It is the same thing as various "weapons" used in "martial arts", most of them did not exist in the military, or have been changed in shape beyond practical purpose. Such as the iconic 牛尾刀 which is the sword that "represents" "Chinese martial arts", but never used by the army.
Another example is the dress in classic Chinese drama are far far away from actual traditional Chinese dresses.