While a high GRE score is required to become a professor, why can't all professors teach GRE prep as well as GREGMAT does?

GRE General
1

While a high GRE score is required to become a professor, why can’t all professors teach GRE prep as well as GREGMAT?

I assume if you can score high on a GRE, you’re good at teaching it also. Einstein said if you cannot explain something to your grandmother, then you don’t understand it. Understand: teach and score high. Not understand: cannot teach and scores low.

My Professors gave me no advice on how to score high on the GRE.
If they knew how to do it, they could have at least gave pointers, but they had no advice or comments.
Rhetorical: How did they even do well enough on the GRE to qualify for a PhD?

2

Depends . Also, most of the answers will be biased towards Greg as he is the most approachable (affordable) GRE teacher that everyone can get. For most of the GRE platforms people only subscribes either to their question bank or for their per-recorded set of lectures thus, their interaction with GRE tutor is very limited to NIL for those other institutions.