That's not exactly true.
America and Germany are members of several organization, such as the G8, TRIPS and World Trade Organization (and soon ACTA probably), which regulate, to varying degrees and for varying purposes, how these nations' companies should operate towards each others' citizens. Additionally, Germany is an E.U. member, which has it's own trade relationship with the U.S.
Among these trade agreements, are stipulations that American based companies must honor to some degree, any applicable German law when doing business in Germany, or with German citizens.
As part of these agreements, U.S. computer game retailers must comply with the USK regulations to some degree, and in fact, many companies go above and beyond the required level of cooperation to avoid both bad press, and a different sort of trouble, unique to Germany.
The BPjM (roughly: Federal Department for Media Harmful to Young Persons)
is a German federal agency which has jurisdiction over, among other things, games unrated by the USK, their sale and more importantly, their importation.
Illegal importation of a game is a crime under the BPjMs jurisdiction, any German citizen illegally importing a game is liable to be prosecuted (including adults, even though they might otherwise be able to legally buy the game from a retailer legally enabled to import such games)
The fact is, international laws regarding Video Game sales are a tangled mess, especially when dealing with particularly restrictive and draconian countries like Germany or Australia. Detangling this mess so that game companies can comply with applicable international trade agreements, be correctly rated, and so that retailers can cover whatever applicable legal hurdles exist. This is not cheap, and the consequences for not complying with the necessary restrictions can be even more so.
Yes, infact, these agreements, laws and agencies do apply equally to online commerce. And thanks to the trade agreements and organizations involved, there are courts in which the German government can bring suit against game companies and retailers violating them. On top of that, the German government could, legally, order German based ISPs to block websites selling digital versions of illegal or restricted games.
You're basically asking EA to pocket all of the legal costs and/or risk violating international trade agreements in order for you to get a game for the same price as a less restrictive country.
Yes, EA could do all sales via paypal in dollars.
Except they'd have to eat paypal's high service fees and still risk the online storefront being blocked in restrictive countries like Germany and Australia.
I admire the principle, but that just isn't realistic at all.
Just be glad you aren't in Australia, you'd have to deal with similar restrictions and every game would be twice as expensive as anywhere else regardless of ratings.\
The 'Import Economy' you're thinking of hasn't existed since the nineteenth century. Wlecome to the age of Digital International Law, nothing is beyond the reach of regulation or litigation.