... ...But our professions differ somewhat. The demand for poetry and the sound of lute strings will never decline. It's worse with your trade. You witchers, after all, deprive yourselves of work, slowly but surely. The better and the more conscientiously you work, the less work there is for you. After all, your goal is a world without monsters, a world which is peaceful and safe. A world where witchers are unnecessary. A paradox, isn’t it?
In the world of The Witcher books, the witchers were so effective at their trade, that over time that they put themselves somewhat out of work.
Now, imagine a world where lawyers are unnecessary. Will that happen?
...I think never. I say so for these reasons:
The world is not fair.
Where there is unfairness, people will always have something to argue over. Money, wealth, resources, labour. Egos, pride. Slights and sufferings, however big, and however small.
And when people argue, there will be demand for trained intermediaries. From among them should arise a class, professional and skilled enough to engage in an arena of dispute (courts, or arbitration, or tribunals) on behalf of others.
In ancient times, we had the sophists. These days we have 'lawyers' and 'litigators'. Descriptions may change. So over time the word 'lawyer' may turn archaic, or shift in meaning. But the profession itself, whose function is to help and deal with disputes between people? Unlikely.
Where there are humans, there will be discontent.
Human discontent is infinite. And if it is we, the humans, who are the 'monsters', then there will always be contentious work to go around. So long as humans see others as 'monsters' (enough to accuse or sue them), lawyers and litigation will continue to exist as a class.
It's not the same as for the witchers, whose witching work will survive only so long as their realm's finite beasts do.