I've never really understood this way of thinking. In my experience, it is trivial to maintain cross-platform applications if you encourage code-reuse in the logic layer and tailor the UI/UX experiences for the platform you are targeting. In practice this usually means writing the client business logic in a high-performant language that can target multiple platforms (I've only used Rust for this, but there are other languages out there that would work well with this approach as well), and using FFI when interacting with the UI layer. Combine this with good message passing practices (to homogenise serialisation/deserialisation and avoid the complexity of having hundreds of different FFI functions with various parameters) and you've got something that is easily integrated in platforms with little headache.

I've seen great success with this approach for most platforms including mobile as it provides the end-user with a great user experience (you can use all the native UI APIs which provides an experience that the user is already familiar with) as well as extremely high performance with a high degree of code reuse.