You need interoperability in a world where you have a lot of heterogeneous chains that need to talk to each other. But why do you have so many chains to begin with? Why isn't one absorbing the user base of the other ones?
The cyclical viewpoint is that pushing for interoperability is a bid for dominance disguised as a blue ocean strategy.
I like the Polkadot project and the Cosmos project a great deal, but I'll note that Polkadot isn't developing its project as a Cosmos zone, and that the Cosmos project isn't putting it's atoms on a para-chain.