For example one of the problem is that not all professions are unionized for example, so o get more profit and power the unions need to stifle innovation and steer the government only toward heavy industry to the destriment of almost every other sector
Also being national they seldom talk directly with workers and plant owners, and prefer to play their hands at the political table, often ignoring the specificity of issues.
And since their decision have national level ramification, every singe one needs months if not years to mature, implement and execute. Like, most national contracts are expired and have wages that are ridicolous by 2017 standards and base salary need to be supplemented in various, highly taxed ways, and new form of contracts are impossible to create (IT for example is hired under industrial or commerce contract, as the gategory didn’t exist at the time and there’s no reasonable way to create it now)
The parent comment might be full of lies, but I’m actually more inclined to believe it when the best you can do is call them falsehoods with no evidence or argument.
The downside is that if the union's approach is too strict, those jobs may simply disappear because it is not feasible to pay those workers more, or it may be cheaper to move those job abroad and import the resulting products.
This also requires workers to struggle and strike not for their job, but for someone else's.
(I am not saying one approach is better than the other, in fact I am usually not too fond of unions, but I am trying to explain the union's point of view)