Couple things that come to mind:

1) SV software culture, kinda coming from Musk. This helps with battery pack management (important), electric motor control (important) and fancy car UI (less important perhaps but a "cool" factor. I think I count autopilot here)

2) Skin in the game. This is a bit meta, but some of the things they've done take some real guts and leadership. In their case it was do-or-die. Things like charger network, or getting the cars sold without dealerships, or building their own battery factory, or maybe the very idea of a production EV. I don't see this with incumbents - even if they have EV lines they could probably shut them down without much impact. Maybe this will not last long, I guess VW promised to switch to all electric new platforms? At that point they are kinda committed.