Thats only because your list has different types. Its a badly formed API and if you really need to support that use case then you can use maps and reflection to handle it.
We used to have strict typed XML. Nobody even bothered.
Not JSONs in general, but a sane API would never return something like that.
> We used to have strict typed XML. Nobody even bothered.
Nowadays there is OpenAPI, GraphQL, protobuf, etc. and people do bother about such things.
Yeah, because it was ugly as hell and not human-readable.