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.
Well, if you think about it, when you deal with a lawyer, it invariably has to deal with the law whereas the other professions only deal legalities as a result and not primary purpose. So the relative consequence is not the same.
Similarly, with the police, because they are charged with law enforcement and being equipped with guns is very different than dealing the local surly person at the market.
That's why I'm of the opinion that certain professions need a lot more oversight and avenues of recourse than others. One would be foolish to think otherwise.
Your point is well worth discussing. The primary difference I see is the nature of the outcome and the way checks and balances work in those processes.
In each of your examples, the person you are referring to has a ton of oversight and proceesses in place to catch errors. (I don't know about nuke engineer, but in general the military avoids paying market wages by recruiting then training then placing).
In the lawyer situation picking the wrong guy can be financial suicide.
When you hire a structural engineer to design a bridge, you aren’t worried that your enemy has hired his or her own structural engineer to undermine your bridge at its weakest points.
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.