It doesn’t go away, it simply changes polarity.
It’s happened many, many times in the past.
I read something awhile ago that claimed the poles reversed about every 60,000 years. Patches of northern polarity appear more frequently in the Southern Hemisphere ( and vice versa) until the poles flip.
Doesn't it depend on what creates the magnetic field ?
The magnetic poles move all the time. According to the data, they keep moving further away from the geographic poles.
Let's say they were fixed and couldn't move. How would they suddenly 'change' polarity ? What would be the mechanism that would explain that ?