Disclaimer- ex Meta employee.

Horizon was horribly managed, but also we threw all of our unannounced projects under that umbrella to make it look better for shareholders when we finally cut it. The original LLM research, smart glasses, and a bunch of other projects were under the "Reality Labs" business expense.

I mean, of course it was a matter of being at the right place and right time, and being able to execute. He definitely was lucky but that alone isn't enough