I could see that 100k years ago, but 780K? It’s a stretch, though in the realm of possibility.
If you take a look at the bones of the people of the time you see no fangs, no claws, small jaws, small guts. Conclusion: we were cooking.
That is the only way we could have gotten enough calories to survive.
And pit cooking or stone cooking is a natural advance once you know how to control fire.