without a change to the system

That's the whole point but it won't change unless we change what we are doing, cause it clearly isn't working.

Those parties are only dominant because people fall in line. If people stopped falling in line and changed who they gave their support to, those parties would no longer be dominant.

Their power relies on our capitulation. If we want other parties to win, then we have to give our vote to them and hope that others will do the same. If I keep giving up my vote to someone else that's a guaranteed way for the person I actually want to lose.

Frankly, I believe the entire system of hierarchical, representative democracy is a failed system to begin with and, especially under the influence of a capitalist economy, will inevitably collapse into fascism. Parliamentary democracy is only marginally better. Until we abandon this system and begin governing ourselves in a horizontal structure, it will never change for the better for the working class. Everything else is just spinning wheels, maintaining an inherently oppressive status quo.