At least in my country (France) it's not any harder than registering as an independent worker (you often use the exact same legal vehicle for both).
The real problem with European tech is that it's too easy for US company to land on the continent, and since they have a biggest market to begin with they always end up stronger than European companies when it comes to addressing the other European markets. The “single market” is a fantasy, every country has its own language, culture and business practices, things that EU's homogenization of regulations between country since the 80s have never overcome and never could have, and because of that it's not harder for an American company to do business in an EU country that it is for another European country.
Since forced homogenization isn't gonna do it, the correct approach would be to put barriers to foreign entry like Evey successful Asian country did in the second half of the 20th century with great success.
Advocating for free trade with a much more powerful country than your is as insane as it would be to advocate to remove the fences in a zoo…