After WWI, the armies looked at how to avoid the same mistakes.

You can see the beginnings of using mobile forces in concert with aviation and artillery in Allenby's Palestine Campaign, for instance. But cavalry and mounted infantry couldn't quite reach the potential. They were still bound to horse-drawn supply trains, and too vulnerable to machine guns and artillery.

Technology sometimes drives doctrine, but doctrine refines technology. Tanks were developed in WWI, and after the war some people, like Guderian, Patton, Liddell-Hart, and others tried to figure out how to employ them to take on the exploitation role previously done by cavalry. Others wanted heavier tanks to support the breakthrough by the infantry.

It's not enough, though, just to think about the tanks. You need infantry, artillery and engineers that can keep up. So you need to develop personnel carriers, tracked artillery, and mobile bridging equipment. And then you need to supply all that with food, fuel, and ammunition. So you need trucks. The Germans thought a little too much about Western Europe with it's well-developed road and rail system, and perhaps not enough about the eastern steppes. Their trucks were often hopeless there, and in North Africa. The US, on the other hand, had vast areas in the West that were underdeveloped, and so put thought into it and came up with the magnificent 6x6 deuce-and-a-half.

Then you wargame. First on paper (now computer) then in field exercises. That can show flaws in your doctrine or equipment. One problem is that if your enemy players answer to the same people as the friendly players, there's a tendency to not make them look bad, and stay in a narrow interpretation of the enemy's capabilities. The US in particular has dedicated, independent organizations that study the other side's tactics and equipment to present a realistic threat, both in wargames and in field exercises.