Bad instruments was what I've always thought.
MD, the distance to some of the closest stars is 500,000 times the distance to the Sun. at the time, they never imagined the stars could be so distant. It never occurred to anyone.
So parallax could not be observed until much later, with more powerful and accurate telescopes. And yet, 400 years later, most of these mouthy people still know nothing about planetary physics, even with all the advantages of modern science.
they really aren’t interested in science.