Can I ask, at what point in your employment did you negotiate for weekends off?
Do you seriously believe people wouldn't get weekends off if it weren't for unions?
I wonder if unions also introduced the 20% time at Google?
Of course if masses of unskilled workers face a bad labor market, they'll have trouble earning good wages and good work conditions. They can unionize, that is, try to form a monopoly, to drive prices up. I think the same people who praise unions usually hate monopolies, which doesn't really make sense. All the issues with monopolies also apply to unions.
The proper way out of it is to increase demand and increase skills.
Unions may help some people at face value, but at the same time they hurt others. Minimum wages prevent some people from getting jobs - many of whom don't even show up in statistics as they are people earning just a few extra bucks. Maximum work hours hurt people who for whatever reason need more money and would like to work more. And other things.