Pace
That has nothing to do with aviation laws or the FAA but USA Immigration and working restrictions
there is nothing to stop you keeping a EASA registered aircraft in the USA but I cannot imagine why many would want to do that
With all due respect I think you might find there is a limit of 6 months for a privately operated aircraft, PA28 or bizjet then the aircraft has to be re-registered to an N reg if you wish to keep it longterm in the USA.
You will find that an AOC operated aircraft can fly to the USA with pax but cannot pickup new pax in the USA to fly to another US destination, private or commercial, the FAA/US government are protecting their own system and citizens.