First problem is that "living wage" is a meaningless term because it will very by multiples depending on where you live and your family size/structure. The next problem is that people dont just do a job that needs to be done, they can literally be worth less than you pay them. If they keep making mistakes, or you cant trust that they will correctly do the job or whatever. It can just not be worth the money or extra labor to employ them.
Right, which is, as the other person said, why you fire them if they don’t do a good job. You don’t keep a mistake-maker and pay them less, you hire someone who can do the job and pay them well.
And how is it ‘meaningless’? You just defined it: a wage allowing someone to live in the place they’re located. So yes, it changes from place to place. That’s not ‘meaningless’, it’s ‘regional’. And you should still pay someone a living wage.
I don’t understand why you’re so opposed to it. Why do you want people suffering and in poverty for providing services? If you work, you should be able to eat and live, full stop. Even if it’s only in the cheaper parts of your town.