> However, the comparable US company can invade my market
Again talk about "invasion", I'd suggest you don't be so emotional so we can have a fruitful discussion.
Aside from that nobody owns the market.
You may feel it is an invasion because the barriers are low to do business as a foreigner, but this goes both ways.
I successfully sold products in the US as an EU citizen without having an office there, so it is possible.
And there are many tech companies from the EU that do the same on a much larger scale.
Our problem is really the legal framework, getting loans for starting businesses, getting investments from private investors (this is getting better though) and bureaucracy.
In the US you can fail and rebound from it, in most EU countries your life is destroyed because you'll be burdened with debts till the day you leave this earth. (or you lose all wealth you have accumulated to this point)
If we in the tech sector weren't so lucky to be able to start businesses with low capital investment I would have never started one because I don't have the rich parents/family that could help me if things go bad.
This is the problem from my perspective that we face here and no amount of protectionism will change that.
On the other hand I'm truly amazed what risks people take to start businesses in more capital intensive sectors in the EU. I wouldn't have the stomach to do this, to me these people seem almost insane.