When it comes to negotiating with the US, far more comes into play than the size of our GDP.
I understand how the EU operates as a bloc in many instances, but you write as though every nation in the EU has similar needs or goals or abilities, etc. We're seeing right now, that isn't the case.
Your willfully ignoring the disparate desires and needs of the individual nations in the EU. They only kind of negotiate as one.
And you are ignoring just how powerful the US truly is. We dominate tech, weapons, military projection, security, oil production, we push around the UN, we control NATO we fuck around in every corner of the world, we meddle and drag other nations into our bullshit, costing them money and lives, we have that size GDP as a single nation and we've been especially agressive and less friendly with our negotiating lately. Everything comes into play when world powers are negotiating, and we have more cards more money and more power.