Changing the system is possible as we've done it a different way before. It just needs political will. No one said it would be easy.
That's what I see as the difficult thing. We know now that any attempts towards socialising the economy will be ruthlessly opposed by the press (even supposedly left wing mouthpieces), industry, big donors, party backbenchers, and the more easily influenced members of the public. To the point that there'll be attempted terror attacks against the party leader making those efforts.
You say it just needs political will, but it needs a person who's absolutely nails and rock solid in their beliefs.