When companies aren't doing well either, demanding more money will only result in bankrupt companies and out sourcing.
It's probably the worst time to do it.
I've only seen unions work well in the long-run with government jobs. The USPS is a good example. Mostly because you really can't fire the workers and the main entity won't ever go out of business because of government bailouts.
Companies are doing amazingly well by any metric. They just refuse to share with their employees.