I mean you say that, but...

1. Western world has been living in liberal democracies for 100+ years, yet labor unions are weaker than ever (both in numbers and power), especially when compared to the union zeitgeist 100 years ago.

2. Worker rights are no longer a hot button issue people rally behind, nowadays it's pretty much all about immigration, LGBT rights, taxation to a certain extent and whatever else. It's legitimately difficult to find a representative in most countries who cares about expanding worker rights and giving more power to unions - best you can hope for is someone who won't suppress them.

3. Relying solely on voting to get expanded workers/union rights leads to passivity from the workers (as in them stopping to do anything outside electorialism to fight for themselves), and there's no guarantee they won't get rolled back later anyway as history shows, with infamous examples being Thatcher and Reagan administrations.

I could go on and make this unreadable, but essentially electorialism isn't the way to go when it comes to workers rights or especially when it comes to abolishing capitalism entirely.

That being said, your comment isn't entirely without merit as there's not that many movements nowadays actually fighting out there for better working conditions outside electorial politics. There are some international efforts though, like International Communist Party or Class Struggle Action who have helped to organize, keep strikes alive or spread propaganda to help the workers in their fight - small scale action but action nonetheless.