Elon's error here is that while Tesla and SpaceX are 'hardcore' type companies that are changing the world and therefore attract hardcore candidates Twitter is

Elon's error here is that while Tesla and SpaceX are 'hardcore' type companies that are changing the world and therefore attract hardcore candidates Twitter is not a hardcore company. It's more like a government department. The temperament of suitable prospective employees will therefore also be different. Twitter is not changing the world with cutting edge technology. Elon has a very expensive lesson in his future.