short answer

Why didn’t scientists in Wegner’s time agree with him?

1 answer

Scientists in Wegener's time disagreed with him largely because he lacked a convincing mechanism to explain how continents could drift. His theory of continental drift went against the prevailing belief in fixed continents and was not widely accepted until the development of plate tectonics in the mid-20th century, which provided the necessary scientific framework and evidence for the movement of Earth's plates.