Good enough by whos standards, the union or management? China is a great example, it's under a communist regime yet they have a greater capitalist attitude than perhaps anyone in the world.
Another example is myself, I'll make well over 100k this year yet do you see me saying "the union promotes everyone to only make 80k average?" Find in the contract or where any business agent says, "Just do the minimum"
Another example that just came to mind that you can relate to, unpaid days off. The union supplies language to allow people to get their 8hrs a day yet people scramble to go home without pay because they are "happy getting by". The union in this example is promoting a higher work ethic than these individuals yet they choose to be "mediocre". That's like saying the union promotes mediocrity by negotiationing high wages so we only have to work 3 days a week.