Haven't been in the military but isn't the tanks = cavalry argument in modern warfare is kinda off. Its the airpower that provides the analogous shock and speed of cavalry.

AFVs are more analoguous to formation fighting heavy infantry that provide anchors in a line and a position for light troops to fall back to. They are powerful force that can engage in slugging matches while they can be taken out by bad terrain and inproper support.

Infantry in this analogy would fall into a skirmisher role providing support for a tank and provide the eyes and ears for the armor and air power as well as fighting where the armor cannot.

Under this analogy, Pydna would resemble the time the British in North Africa brilliantly tricked the German Tanks into the soft sand where they became ineffective.

Likewise, Gaugamella would have resembled something similar to the Soviets rolling through the Fulda Gap. The NATO forces would have to hold against the numerically superior Soviets long enough for Western air superiority so they could bog down and destroy the Soviet advance.

Something like that...

*flees before Ludens shows up*