There are plenty of examples unions being corrupt or allowing corruption, waste and inefficiency to occur however they are more vital now than ever considering how little regard corporations have of workers in all kinds of industries. Tesla is a perfect example of it especially looking at tweets of his threatening employees that they are fully expected to show up or else. Piss off Elon.
There’s also plenty of room for unions to remake themselves to better serve the people that they protect, something that would be a much bigger hassle to accomplish directly with companies as they primarily serve themselves and their investors.