The unobvious but major thing missed is that hiring the wrong lawyer is far more expensive than an additional $300 per hour
You could say the same for any number of industries - hire the wrong structural engineer and that bridge or building will collapse, hire the wrong nuclear engineer and attack sub might run out of power while engaging the enemy, hire the wrong electrical engineer and the airliner's control system may fail, etc - and yet only very few people in those industries can ask for over $250/hr.