The question that the OP needs to clarify is; What have the French replaced Static Defence Doctrine with?
Just 'ditching' a doctrinal concept NEVER happens in all of history, what you see is one doctrine being replaced by another one, that is suppriour for fighting with the weapons and manpower available.
For instance in Viet Nam, we saw the Viet Cong replace conventional warfare tactics, with those of asymmetric warfare, because in those early battles they got their arses whooped.
Hence what doctrine is better than Static Defence that can cope with Frances position during the 1920s and 1930s?
Considerations:
1. France lost a hell of a lot of men during the Great War. Therefore every solider has to have a better 'kill efficency' for future wars. In principle this means better equipment.
2. France has run up a fair amount of debt fighting the Great War, therefore high cost programs cannot be budgeted. In principle this means non cutting edge technologies and reduced defence expenditure.
3. France has a colonial empire, naval equipment must make up a fair amount of the armed force expenditure.
4. Frances future enemies are likely to be the Germans again.
5. France doesn't want to fight on French soil again due to the tremendous cost in rebuilding.
6. The Great War was the second industrial war, in which European Nations learnt the concepts of arsenal and mass weapon production (the Americans learnt this in the American Civil War in 1864). In principle this means standardisation of equipment and economies of scale.
In principle the Static Defence Doctrine with hte Maigot Line fulfils the vast majority of all these considerations, and so the historical French doctrine was in many ways the perfect decision to take.
Only with hindsight can we see that the lack of a full line into Belgium and the fall of Czechslovakia allowing the Germans to perfect assault tactics meant that the breeches of the Maigot line and through the Ardennes sunk that strategy.
However what we might want to consider is what if the French, line the Russians develop a tank school during the late 1920s and early 1930s that perfects the 'infantry tank' concept, with larger turrets, fast cross country mobility, defence in depth and operational deep battle?
This coupled with the Static Defence Doctrine would mean that the French would prepare a deeper front concept, rather than during the expansions of the line during the 1930s they would opt to harden the rear areas and general Picardy and Champagne region.
With better tanks, and an elastic defence doctrine coupled with local hardened positions it would mean that the French would have been able to blunt the Ardennes attack in 1940 and the BEF would have been able to close in from the Calais region. Overall creating a very similar situation to WW1 until the German gamble collapses entirely from the fact the Panzer I tanks armed with little more than machine-guns are being comprehensively being taken out by French infantry tanks and AT guns.
The Armoured Scherpunk concept would have been completely discredited, and the weakened German armed forces would have been forced onto the defensive as the British and French rapidly reconquer Belgium and move into North-west Germany, since their tanks and tactics are specifically aimed at breaking trench defence, which is what the Germans will fall back to because their 'new doctrine' completely failed them.
It is likely that Hitler gets taken out at some point internally as the French and British having liberated Belgium begin themselves to dig in.
At some point Holland to will be liberated/get in on the fight and with a much larger front, and with less ability to intervene in North Africa or even begin Barbarossa the Germans will likely be stuck in another war they cannot win.
Since the Germans historically never were able to upgrade large numbers of their troops to the automatic SMG weapons of the MP 40 and similar (unlike the movies), the Allies with the Thompson, BAR, Sten, Lanchester and other similar weapons will overall be able to break the trench stalemate more often and with fewer casualties.
This war could very much be over by mid/end 1942. This time Germany will likely be destroyed and dissolved into Bavaria-Austria and Prussia-Saxony with Poland getting back all its territories in the west to help prevent Stalin’s Soviet ambitions.
However as a result of no Russian front, the Russians may never get to full Superpower status, yet without the horrors of the Eastern front, they may likely have a population explosion during the Cold War that leads to them outnumbering this TLs version of NATO and consequently being the economically dominant nation of the world. Thus they may end up winning the Cold War and we today would live in a pro-socialist world, rather than pro-capitalist.
