Will the Oktoberfest 2021 be three weeks long?
Short answer: most likely not.
After the postponement of the 187th Munich Oktoberfest until 2021, it didn't take long until the city's yellow press called for its extension to three weeks. However, no officials discussed this topic yet.
As such an extension comes with an extreme effort to adapt existing structures, just think about all the additional personnel you would need, we believe it's almost impossible that this will become reality. Additionally, the Theresienwiese's district council typically opposes any kind of intensification of the use of the festival grounds.
However, we don't think it's absolutely unrealistic to extend the Oktoberfest by one day. In the past, a general extension by one day has been discussed by various city counselors, and once, for the 200th anniversary in 2010, it has even been realized. If the Oktoberfest will happen in 2021 at all, is a different question.