300wh/kg is not where we will ever see any conventional lithium battery chemistry get.
Best mainstream cells cars are made with today are all around 200wh/kg.
240wh/kg NCM cells are there, more or less widely available, but they are almost the same stuff with higher rating, and lower cycle life. Manufacturers basically nudging digits.
If they reach same 200wh/kg, along with equal cycle life to LFP, it can be big.