Whenever any of said countries stop contributing so much money to EBU. Interesting fact - EBU changed the rules of relegation in the 90's a few times to make sure none of those countries get relegated. It was fine in 93 and 94, but there was a problem in 95 where Germany came last. They made a PQ round instead of relegating the bottom countries. To some people's surprise, Germany didn't make out of the PQ round. So, they changed it again from 97 that the past 5 editions will count towards being/not-being relegated. But... France started doing badly and Germany, too. There was a risk of them being relegated, so in 99 EBU said "feck it all - make them qualify for the final regardless of anything, lulz".