The labor unions have been in decline for several decades. This is because of a fundamental truth about economics that labor unions don't seem to realize. The truth is that it is skill level much more than labor supply that determines a persons wages and benefits. Workers with more skill will realize greater working conditions. Collective bargaining will become increasingly irrelevant as automation and robotics advance.
Yes, I think that right to work laws have a more prominent future in America, because they have made more strides in recent years. Scott Walker in Wisconsin was the first to curb union power, followed by Rick Snyder in Michigan. Breaking the unions was critical to bringing jobs back in these states.
Labor unions will rise because of the internet bringing people closer together. Union meetings will be set up easier. The employer's unethical practices will also be exposed even faster by anonymous submissions to a company page or to other members. This will allow the members of the labor unions to be employed fairly.
I believe labor unions will have a more prominent future in America. Many employees in America are being taken advantage off and there are many people in America who are underpaid. Right to work laws have hurt employees and left many in positions that offer no chance of advancement. I believe employees will eventually protest for more rights and think unions will wise again.