The times are evolving, technology is advancing, and the pace of military technology updates far surpasses what most people imagine.
The top-end thermal imaging from a decade ago pales in comparison to the most common models now; what was once exclusive to a few elite is now available to anyone with money.
Night used to provide one-way transparency to advanced militaries, but now, there's hardly any such thing left. Gao Guang and his men had night vision devices, but so did the enemy, so the era of approaching the enemy under the cover of nightfall has mostly vanished.
However, to always stay at the cutting edge of technology, money alone is ultimately not enough, as the highest-end military technology representing a country or an armed force can't be bought with money.