This isn't VAG specific, but to be competitive in the US after considering shipping, export taxes, testing and certification for the US market there has to be something we get shorted. It's either that or you would have a $50k Golf.
Also when we're talking about headlights and tail lights, the Euro standards are not the same as DOT so they would need to make a completely different part for the US, not just send us the lights from other countries that are RHD.
The tech eventually trickles down, or you just buy "illegal" headlights and tail lights and do it yourself