What could knock out France is greater commitment to Operation George. Take the Bethune coal mines and you'd probably see French munitions production all but crippled.I don't think France is knocked out though it could mess up Allied counterattack until 1919.
What ever advantage (real or imagined) the German army might have enjoyed over the Western Entente in 1914 - it certainly did not enjoy in 1918 and was at a massive disadvantage logistically.
It cannot advance faster than the British and French armies could concentrate forces to prevent any breakthrough (this had pretty much been the case since 1915) and once it had outrun its railheads ability to supply its armies it could not even try to match its opponents ability to do the same.
The spring offensive was a desperate roll of the dice by a leadership that should have known better and should have been seeking an end to a war that it was incapable of winning at that stage of the war.
They struggled to get close to Arras against the weakest point of the BEF - Amiens is several times further away from the front lines and therefore the German Railheads than Arras is.
All the Spring Offensive achieved for Germany was to squander its best troops - I cannot recall who wrote it but I recall a quote regarding the state of the German Army following the Spring offensive was that it had plenty of Divisions just not many regiments to put in them and this allowed the 100 days offensive to be as successful as it was overrunning the German Railheads in Belgium.
Best bet would have been to Turtle and try to hold while sending feelers for a favourable peace while they still held parts of France and most of Belgium
See the dotted red lines on the map below to show the maximum limits of the Spring offensives - Ameins is what 3 or 4 times the distance advanced?
I think that map is August 30th post early August Amiens counterattack, so they were closer than that (not disputing the jist of what you are saying though about the abilty of the Allies to reinforce any selected point quickly)
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If you go with the thought that a German 1918 offensive is ill fated, The Allies may be willing to make peace if:
a) Germany gives up Alsace Lorraine
b) Germany gives up colonies
c) Reparations made to private parties in France and Belgium
d) status quo pre war elsewhere (maybe Germany could get some compensation in the east but nothing like March 1918).
Otherwise they wait and see until 1919 when the Allied force is overwhelming, I doubt if Germany politically would agree to those terms, although it would be in their best interest.
The thought is that without the German offensive, the Germans would be in the Hindenburg line at full strength and the 100 days wouldn't work.Good luck getting France to agree to such light terms unless the 100 days fails similarly.
The thought is that without the German offensive, the Germans would be in the Hindenburg line at full strength and the 100 days wouldn't work.
Then your looking at 1919 with the Allies with loads of tanks, and a large air force, military superiority on all fronts for the win. A long way off.
So maybe the Allies agree to terms to avoid a year + worth of casualties and costs. (and its not much less than they got anyway). But yes a lot can change and the Allies may never agree to terms, which is probably why the Germans committed to attack in 1918 OTL.