The Maginot Line is an archetypal example of 'generals fighting the last war'. The Nazis famously just went around it through Belgium.
But, the Allies went through Germany's equivalent Siegfried Line.
Was the Siegfried Line not as defensible as the Maginot Line? How did the two lines compare in technology, etc?
While not having a definitive answer to the exact strength of the Siegfried line, I'll point out that German commanders did describe it as rather unimpressive prior to the start of the offensive against France in 1940, and a real effort to strengthen the defenses wasn't made until after the D-Day landings in 1944.
I do, however, want to pick a bone with OP's assumptions about the French Army War Council and the Maginot Line.
The purpose of the Maginot Line was to allow time for French mobilization, not to ward off an entire German offensive. In fact, Gamelin assumed (and was correct in his assumption), that the Germans would again invade through Belgium, as they had in the last war.
Even the notion that the main German thrust would come through the Ardennes was accounted for, with an estimation in 1938 that it would take the Germans roughly sixty hours to move through the hilly, forested region (this estimate proved correct in 1940).
The Maginot Line was successful in forcing the Germans around it, and limiting the geography where an offensive could be conducted. It was never intended to completely stop an attack on its own.
Jackson, Julian. The Fall of France: The Nazi Invasion of 1940. Oxford: Oxford University Press, 2003.