One reason for some delays is translation into the local language. Some countries want their books and movies to be in their language instead of English.

Another reason is marketing. Even if the local language is English, they will want a marketing campaign specific to the that country.

Sometimes it is just a matter of different schedules. Even if the work is being published in different countries by the same international publisher, the divisions of that publisher might be operating fairly independently in each country. The French division of a publisher might have various books in French by French offers on its plate that it considers higher priority than some American book that is coming in via the American division.

As far as translation delay goes, this could become less important as more people speak English. In the EU, over half the population speaks English as either a first or second language, and it is the first foreign language in secondary schools in every EU country (except those where English is their first language, of course).

There could become a time when people in Europe, even in countries where English is not their first language, prefer to get their American books and movies in e-form as soon as they come out, instead of waiting for a translation. These people won't need a local advertising campaign, and won't be dealing with the local division of the publisher.

If enough people in non-English speaking countries start getting American books and movies in English instead of waiting for a translation, that could make it less likely that the publishers will bother with a translation.

It will be interesting to see if that causes any controversy. I could see there being some backlash against that, with some thinking it is marginalizing their culture.

Basically, the internet has a homoginizing effect, but there are some things people do not want homogenized, so we are in for some interesting conflicts.