What counts as affordable when developing a rocket, is reportedly between five and six billion dollars. The European Space Agency makes no secret that its goal is to compete with commercial entities like SpaceX, which already has a program to deliver supplies (and humans) to the ISS.
No surprise, given that SpaceX's very own Elon Musk already went on record saying that the current Ariane 5 rocket stands "no chance" against his competition. SpaceX doesn't need to worry just yet though, as the roadmap for Ariane 6 wouldn't see a launch until the end of the decade.
