Okay, time for the resident modern history buff to kick in again.
The Maginot line was a series of defense works which for about 80% were underground. The only bits sticking out were firing slits, and gun turrets. Hardly a wall I'd say. And yes, it was a mistake to only have it running from around the Swiss border, and end at where the French/Belgian border began. But this was hardly because they were lax. The Maginot line was constructed even before uncle Adolf came to power, and the French had close ties to the Belgians, whom would not be very happy if all of a sudden they saw massive fortifications spring up on their borders. Kinda like saying "yeah I like you, but I'll just unroll this barbed wire between our two backyards". Just doesn't work that way. The Maginot line as it was, was such a formidable obstacle, that the one army who did have to attack it (the US), suffered terrible casualties, and they attacked it from the rear!!!
If you want to talk about acts of senseless sacrifice, then don't forget about Market Garden, or the US campaign in the Huertgen forest, 24.000 casualties over a piece of real estate that was strategically worthless. The reason the French gave up as quick as they did, with the bulk of the French army not yet engaged, is because the French still had the Great War in their minds, and were not ready to make such sacrifices again. The Germans were, for a number of reasons. National socialism had imbued them with a sence of vengeance on the French, and the German population at that time procreated faster then the French. In other words, the Germans recovered quicker from the terrible slaughter of the Great War than the French did. If the French were to take such casualties again, it would more or less annihilate the country. It ain't just about who's got the biggest tanks, because at that time German tank design seriously lagged behind allied tank design (a situation completely reversed from 1943 onwards).