Imagine there was a society in which blue eyed people are referred to with blee/bler pronouns, and green eyed people are referred to with glee/gler pronouns, and one day someone from that society saw a brown eyed person and had no idea whether to categorise them as blee/bler or glee/gler
I thought the dropping of grammatical gender was a consequence of the creolisation of Anglo-Saxon with French to form English, not of Danish with Anglo-Saxon???
The process took many centuries, and Norman French did play a role, but it certainly started with the Danelaw.