Where did you read this? According to OAG - MAS will continue to route MOST European routes via VIE.
MAS and Lauda have together successfully built the KUL-VIE airbridge over the last few years - so I don't think they would be so quick to drop VIE completely. Besides MAS just restarted their Zagreb route not too long ago.
MAS may redirect some flights away from VIE in favour of ROM in the future - as MAS comes closer to joining 'Wings' with Alitalia, Northwest and KLM - but that may only happen in March 2001.