There are other origins of power but votes are special because they control the law.
No votes do not control the law. They elect the government, who controls the law,
The government can be influenced by various means. Voting is but one of them.
Nobody cares if you do not like other methods, such as strikes and protests, they are still effective. And the owning class already uses other methods, such as lobbying and outright bribery, so to constrain oneself to methods that don't work is voluntary surrender.
Which protests are not ignored?
Pretty much every civil rights and liberation movement around the world has been accomplished through a diversity of strategies, which almost always include protest.
If citizens debate before the election about what they want and coordinate their votes, then the state represents their will.