Yeah, it seems impossible for ESA to act rationally in this regard when bound e.g. by French veto. The only opportunity would be for individual countries (like Germany) to fund such rockets alone, but that seems unlikely due to cost (and the fact that they already pay for ESA). Without substantial investment, companies like RFA don't have the means to create a larger rocket, due to heavy international competition.

Not even NASA could resist developing their SLS rocket, which realistically should have been replaced with funding private heavy lift rockets. And that is despite the fact that they are much less politically constrained than ESA.