Why did well-known scholars at the time of the Promised Messiah (as) not mention his coming?
Because those sent by God are almost always overlooked by the prominent people of their time. It was no different with Jesus (as) and Moses (as), and it is no sign of falsehood.
The question often goes like this: if Hazrat Mirza Ghulam Ahmad (as), the Promised Messiah, truly came from God, why did the famous scholars of his time not report that God had shown them his coming? The answer lies in the history of the prophets themselves.
Jesus (as) was not mentioned in any Roman chronicle during his lifetime. His name appears there only long after the events of the cross, and even then only briefly. Moses (as) shaped the history of religion like hardly anyone else. Yet he is found in no inscription of the Pharaohs and in no Egyptian record. For the powerful of that time it was as if nothing had happened.
This is no sign of falsehood. If anything, it is a sign of truth. Those who were once thought insignificant are now respected all over the world. The prominent people who found them unworthy of mention are almost forgotten. With time this gap keeps growing. The verses above show that it was the same with other prophets. The great expected the truth to come from one of their own and overlooked the one whom God had sent.
So if the same happened to the Promised Messiah (as), it is not surprising. More important than the silence of his contemporaries is the question of what has become of his work. When a movement grows steadily over a long time and gains respect in many countries, that speaks for itself. Anyone can examine this development for themselves.