You can't force change, sure, but that doesn't mean you can't be part of it. Individuals can and do join political parties and become influential within them. Political parties win elections and ultimately set policy which can start to change things.

None of those things happen quickly, and most people don't succeed in their attempt to do it. That doesn't mean it's not possible. I'd argue that it's a feature of the system that the system makes it hard to change course - it averages out the extremes.