they do other things to reduce costs E.g. splitting up kit lenses and selling camera and lens seperately, if people return an item under DSR then they are more likely to sell the camera as new despite it being opened. They can also avoid minimum pricing rules.
Another big difference is the regional price differences. Pricing in china might be 20% less than Europe for example so a chinese model where they swapped the charging cable will see a big saving even if they pay all taxes.
However avoiding taxes and duties is a big part of the difference. I looked at a few lenses recently at B&H without sales tax included and compared to DR, taking into account the 4% cash back from B&H there was almost no difference, typically just $20-50 or a couple of % depending on the lens. You can also see that looking at grey pricing on B&H, the prices just aren't that much lower when taxes are equalized.
For example, Sigma 150-600mm Sports:
B&H is $1999, 4% cash back so $1919. Digital Rev is the cheapest Grey, price $1859. So $60 cheaper but you get whatever warranty DR provide instead of a 5 year official Nikon US warranty which is worth so much more than $60, let alone the customer service differences.
Sigma 24mm ART, $799 from B&H with $% cashback = $815, the cheapest grey import is $799. I'll take the 5 year Nikon warranty for $15 please.
Nikon 300mm F/4.0 PF, $1999 on BH,with cashback that is $1919. Digital Rev price, $1999. I would much get paid $80 to have an official Nikon 5 year warranty thank you very much!
However you occasionally get some oddities. E.g.a Nikon 300mm f/2.8 is cheaper in the UK than The US despite 20% tax difference.
