I think one issue is that Apple themselves prohibit it. From their App Store Review Guidelines, section 5.2.2 [1]:

"5.2.2 Third Party Sites/Services: If your app uses, accesses, monetizes access to, or displays content from a third party service, ensure that you are specifically permitted to do so under the service’s terms of use. Authorization must be provided upon request."

And Apple also prohibit you from doing so on parts of their website, from 4.5.1:

"4.5.1 Apps may use approved Apple RSS feeds such as the iTunes Store RSS feed, but may not scrape any information from Apple sites (e.g. apple.com, the iTunes Store, App Store, App Store Connect, developer portal, etc.) or create rankings using this information."

[1] https://developer.apple.com/app-store/review/guidelines/#int...