"Easy" only fails to be a measure of cost if you don't account for all the people involved.
The sum total of amputation is much harder than fixing the limb, assuming it's possible. Yes, it's easy for the doctors, but it's hard for you.
If fixing mold in a house is cheaper than building a new house, that's telling you that it's easier overall. It might look harder, but that's because much of the difficulty of building a new house happens off-site, in the felling of trees, mining of gypsum, fabrication of pipes and wires, etc.
If Tesla is doing warranty replacements instead of repairs it's not because it's "easier" in the sense that the technicians do less work at the expense of the company, it's because it's "easier" in the sense that it's less effort and money in total.