The Mongols too had a technology that completely altered warfare and gave them a huge advantage: the humble stirrup [1].
The other side of the technology coin is organization. The Romans improved on the Greek phalanx (eg maniples, cohorts). In more modern times we have combined arms operation.
Monogol military organization is really interesting. Most were horse archers. The important thing here is that each Mongol horse soldier typically had 2-10 horses. Why so many? Horses would tire and get injured. Troops could switch to a fresh horse several times a day and greatly extend their range and speed. The speed was really devastating. Of course littered in here was a fairly standard military tactic of the false rout. Units would appear to run away and overeager opponents would give chase, overextend and then be drawn into a trap and attacked from all sides.
But the subject of grass is an interesting one. In addition to having fresh horses to ride, those horses also provided milk to the riders. This meant that a Mongol army could extend far without having long supply lines, which are the bane of any military operation (just ask the Russians).
Beyond the grassy steppes I imagine the Mongols were forced to do what other militaries had to do: forage. "Forage" is a really interesting word and a horrible euphemism. It really means to take by force if necessary whatever you needed from wherever you happened to be.
[1]: https://arstechnica.com/science/2017/05/the-mongols-built-an...