There is a diminishing level of returns as you get into the higher end helmets. Same goes for anything - such as high end leather jackets.

I have an Alpinestars MX-1 jacket. MSRP is $599 and Alpinestars now has a thing with vendors that they can't sell it less than MSRP. The label says made in China. My cheap Cortech jacket is made in Pakistan. Obviously both are not coming from a high end leather factory in Italy... sure the MX-1 fits better, has nicer lines and is overall nicer made. There's better attention to detail, but the Cortech will work just as well.

My point is that for 20% of the price you can get 80% of the way ... if it's worth it to you is a matter of taste. You aren't getting 6x the helmet for 6x the price.