Subsidizing?
The price difference is due to currency exchange and Sales Tax excluded versus Value Added Tax included.
Hopefully you understand that in the US products are listed for sale without sales tax ( which is addded at checkout ), and in Europe all products are for sale with VAT included. Electronics carry a 20-25% tax because electronics are a luxury.
That is how with an even exchange rate, a product will be listed for 100 USD, but effectively 105-108-110 out the door. ( with two or three exceptions, a few states have no sales tax ). While in EU countries it will be listed at 120-125 Euros, typically.
And, so, yes some people who travel abroad would buy phones, tablets, cameras, lenses, ... on their trip to the US, to the buy retail at the lesser tax rate, or in a few states avoid sales tax altogether ... which is significant when we're talking about anything from 1k to 2,5k etc purchases. There is a very busy shopping area in the corner of a state, a few hours from my location ... super busy all the time, most cars typically are out of state, to go shopping tax free.