it is a defacto 'duopoly', or an informal cartel... plenty of laws around it if you are not too lazy to google them...

Words Mean Things.

https://www.investopedia.com/terms/c/cartel.asp

“ A cartel is an organization created from a formal agreement between a group of producers of a good or service to regulate supply in order to regulate or manipulate prices. In other words, a cartel is a collection of otherwise independent businesses or countries that act together as if they were a single producer and thus can fix prices for the goods they produce and the services they render, without competition.”

Do you have any evidence that Apple and Google are conspiring illegally to set prices? Are they talking to each other to agree on price?

“Informal cartel” has no legal meaning.