A lot of contract-lawyering involves getting ahead of when things go south and the two previously agreeing parties find themselves in disagreement.
If the expensive person is still better at getting what _you_ want from a contract then it’s always worth doing that.
There’s a reason lawyers are so expensive to begin with - they do very complicated stuff with very expensive consequences if done badly.
The interesting question is whether AI can fill a niche these can’t — or, alternatively, help a layperson evaluate a contract they’re asked to sign better than they could themselves.
Contract law has evolved because transfering the ownership of things is fraught with difficulty. Ownership as a concept itself is notoriously hard to define.
Consider housing - when you buy a house you own that land. Except if its an apartment, you just own the internal walls. Or when the government aquires your land through eminent domain. Or mineral rights - which don't belong to you, you just own the top 5 feet of topsoil. Or if you neglect a property and some squats in it. Or if you were given a fraudulent payment, and they take back the property.
Just getting people to agree is notoriously difficult when people have different often conflicting desires.