Earlier quoted context omitted.
The article mentions that the actual work takes a few hours, but the wait to get the machine actually serviced was 3 days. That is totally store dependent and very clear in the article.
What isn't clear is why he needs to part with his machine for 3 days. Why can't they schedule they swap, and have him come in and wait?
For one they can't predict when they are going to get around to your machine. There may be 100 repair orders in front of yours, might take 1 day, might take 2. They can't possibly set up a system where they send you an alert to say "You are next in line, please bring in your laptop." That would cause incredible delay when that person doesn't show up and you have a tech repair guy waiting for a machine.