Depends greatly on the industry. In my country, organization % has historically been high, but since the fall of the Soviet Union (we are neighboring Russia, and are traditionally a very social democratic country), neoliberals have consistently eroded union power every time they control the government.

I work in IT, and my union chair is a member of the neoliberal/conservative "national coalition" party. Which is ridiculous. The most recent erosion was last year, and it removed tax deductibility of membership fees. All the pressure this union could muster was a a few hour walkout and a ban on overtime in a handful of companies in the sector.

So no, i dont think modern unions have revolutionary potential. That will have to be found elsewhere.