Read my comment again, I was positing perhaps the author of the article talked to 100 repair shops. Yes, there are certainly more repair shops than that worldwide. I was just drawing a line from what data the article has to what we could guess from it reasonably, each step trying to give the benefit of the doubt to the problem being as widespread as we can infer from the article.

Number of google results for a keyword doesn't really give a good indication of how many stores there are for that thing in the world. 473,000 repair shops would be 1,000 for every Apple Store. I'm sure there's a lot but that seems a bit high.

Regardless, I didn't attempt to draw the line through number of iPhone repair shops in the world because we have no evidence whether all repair shops in the world are seeing this problem, only the ones the author of the article talked to.