Actually it's super easy for any EU company to sponsor a so called blue card, the salary requirements are laughably low. I think the reason why so few companies do it is because they're simply not aware of its existence
Indeed, if OP equates EU to Europe, but doesn't answer the language question. IME so few companies do it because there's little demand. The east of Europe is relatively poorer (in pure financial terms) than than west, and it's far easier to hire people from those countries who are already in the EU/Shengen than outside.