Argument: I do not see a single [union] effective at "Stifling CEO's from becoming rich".
1st Proof: American Automakers produce low quality cars.
2nd Proof: The only thing keeping them in business is lobbying from American Lawmakers.
Your proof has nothing to do with your argument. At all. They're not related. They're also very subjective and impossible to actually prove. They're not proof; they're opinion.
A more effective argument would be:
Proof: The largest Union employers are x, y, z, and their CEO's make $x, $y, $z.