I keep hearing that but when I dug a bit into it to do some ASO, the impression I got is that it's simply not easy to game in name of Search Engine Optimisation because the consensus is that the search engine only looks into the App Title, subtitle, description and keywords and the ranking is affected only by the App's performance. SEO people seem annoyed by Apple that they cannot get their wallpapers app for the "stocks" keyword, so I have a very little sympathy. When they complain that App Store Search is dumb, they essentially mean that If I want to rank up my wallpaper app "stocks" and figure a way to people use it every day. They have all kinds of tricks for Google Play but the ASO tutorials are rather dull, recommending stuff like picking an appropriate title and doing A/B tests on the keywords.

As a user, I tend to be quite happy with the search results in the App Store, I don't remember any time where I could not find the thing I am looking for.