Henri McPhee
Illuminator
There is a sensible opinion about all this at a different forum with which I agree:
Let’s see… Munich, 1938. Appeasement fails and the conference breaks down. Hitler returns to Berlin and orders to go ahead with Fall Grün, the plans to invade Czechoslovakia. What would happen next?
My guess is that everyone would be caught with their pants down. The Germans would have the advantage, but they wouldn’t have the full power of their mechanized army or the Panzer forces, so their invasion on Czechoslovakia would be a half-powered Blitzkrieg.
The Czechs would possibly be able to fight back and hold their ground with their border fortifications and Skoda tanks, and maybe they would not be overrun as quickly as Poland in 1939. But eventually they would be defeated anyway. And also Hungary and Poland, of all countries, could possibly stab them in the back to take over some territories (Slovakia and Tesin district).
France and Britain? The most unprepared probably. If the French army was somehow unprepared for 1939–1940, in 1938 such unpreparedness and stagnation would be even worse. Britain would start the war with a weaker army, a Royal Navy without their King George V-class battleships and a much weaker RAF, composed mostly of biplanes (Gladiators and Furies) and some few Hurricanes, and no Spitfires at all.
And the Soviet Union? With the Great Purge going on in full swing, the Red Army would be in full disarray, so it would be difficult to mobilize them.