As was pointed out to me a few months ago (and I argued against it, but it turned out I was wrong) French funding of the Maginot line was actually fairly small. It is the mindset that needs to change. However, they need British help or France won't do it. Fighting Germany alone was impossible as 1871 showed.
France had more tanks than Germany
France had better tanks than Germany
France had more artillery than Germany
France had bettery artillery than Germany
France had better anti tank guns than Germany (not counting the 88mm AA gun which wasn't supposed to be an AT gun)
The problem was France was utterly woeful in AA defenses (their two most common weapons being either an 8mm machine gun or a 75mm gun on the back of a truck)... so in a fluid front their ground forces just couldn't protect themselves from Stukas and HE-111's bombing the living hell out of them
However France had a massive and well equipped field army otherwise and could shield the overwhelming majority of the border with the maginot line which was more or less impregnable... the problem was that they took all their best units and lunged them into Belgium and the Netherlands where they met and did a good job fighting army group B... unfortunately they didn't do a great job screening their right flank and the Germans hooked around them, cut their supply lines and pocket them
If France stood on the frontier (as political difficult as they might have been) the Germans wouldn't have gotten anywhere