Anti-trust law in US & EU depends upon actually having significant market share. iOS has a significant minority share compared to Android, so it doesn't matter that Apple is bundling their own apps. The same logic applies to Bing, which employs many of the same anti-competitive tactics Google has used historically, though because market share is so low Microsoft will not garner any sanctions/fines (unless it becomes more comparable to Google.)

EDIT: per the OneDrive argument on Windows, I think you might have a point - though Windows is pretty open to deep integration with competitive services like Dropbox or Google Drive, so my guess is that MSFT would just have to offer an easy way to uninstall OneDrive, maybe? (or at least disable it.)