Any company can ask for interoperatibility with whatsapp. None of them are, because it's obviously against their interests.
The DMA will change nothing in this regard because the "many apps" approach is the most beneficial to users.
> obviously against their interests
Would love to know how it is "obviously" against my interest to make a chat app and have 3.3 billion users adressable instantly. Bad for internet health to be still tied to Meta, sure, but the damage was done and this is a way to reverse it.
> because it's obviously against their interests.
Why? I'd love to be an alternative whatsapp client with all kinds of new features that the official client doesn't have. Obviously you say you're building a compatible chat network, but the reality is users are just using your client to talk to whatsapp users.
Eg. one feature I'd love is some AI to automatically take any date and time someone mentions to me and put it as a draft event in my calendar. I miss so many events from big group chats I'm not paying proper attention to and suddenly everyone is saying "Whoa, you didn't come to Johns 50th birthday?!? Why not? We invited you months ago[in a group chat with 100 messages a day of mostly memes]"