As explained, the EU can easily switch export nations
LOL and how?
Developing countries by WTO rules have higher tariffs than developed countries, so even with US tariffs that's still lower
Second issue is purchasing power and other currencies are not doing so well against the USD so you are basically selling for peanuts and get deflation. Iran have an economy the size of Michigan and South Korea is slightly smaller less than Texas so instead of convincing just 1 country there's now 30 other developing countries.
There are no equals to the US consumption power. Total private consumption is approximately 67% of US GDP. About 3x larger than China and 1/3 larger than EU