Helps with salary gaps within those countries, but salaries are still laughable compared to US software engineering salaries. Does anyone know why that is?
Demand: US has much more investment in pure-tech. In EU a lot of SWE are working in IT offices of non-tech companies. So the job market in the US is more competitive.
Supply: In the EU university is easily accessible, meaning that there are thousands of universities pumping hundreds of thousands of graduates a year. Plus, now they even invented the Blue Card to make it easy for skilled second/third worlders to immigrate to the EU.
Listen to the MBAs and they'll tell you there's a shortage of developers everywhere. What they really mean is that there's a shortage of devs willing to work for what they're willing to pay.