"To that effect, it's a broad misconception held by European gamers that the US ratings system is its own problem, or that what affects it won't affect the European markets. Many big publishing houses (and a bulk of developer studios) reside in the US, and it accounts for a tremendous amount of game sales. Therefore, the cries from Congress for a harsher rating system there, more government oversight, or even chains like Wal-mart flexing moral muscle by refusing to carry certain ratings will alter the games that the industry releases as a whole. When such a large market ends up closed off to a game, there may be too many development costs for it to ever be profitable. Add to that the reality that the legal enforcement idea of the UK simply couldn't be effectively implemented nationwide in the US (too much land to cover) and you've got a problem desperately needing a solution."
Read on at Bit Tech.