From my experience in Java it is pretty simple using a library like Jackson. You define the types you expect to read, maybe add some annotations, and then it's one function call to deserialize. IIRC Go has something similar in its json library.
Wouldn't it just be worse with XML, though? I get that people don't realistically parse it themselves and libraries are smart enough to use schemas to deserialize, but there's nothing inherent about JSON that makes it unable to conform to a schema or be parsable by libraries into native strongly-typed objects the same way.