There is a difference. Its the negotiation card. Apple could set DDG as the default search engine and not lose 1 customer. They can make fun of Google all day long.
DDG is reliant on Bing. If Microsoft gets upset with them, withdraw, DDG dies. Firefox only source of income is Google default payment. Google withdraws that Mozilla shuts down.
If Google just as much upsets Apple, Apple could buyout something like Brave Search or Mojeek and set it up as the default search engine and Google would be in bigger trouble then. less users -> Stock price down -> CEO fired.
Apple does not care about privacy. Apple business model relies on selling hardware+software. Google doesn't sell much, they really on data collection and advertising. Apple found itself in the position to use the privacy card to win customers so it used it against Android, Google Drive, App Store, and Chrome.
When Google was paying Apple $8-12B to be default search engine, Apple welcomed them with wide arms.
Companies that care about privacy like Tor Network , Proton, Mullvad, Debian, or
FSF would never do that kind of agreement with Google.