Misuse of checked exceptions pre-dates this advice and some of those libraries are very slow to go away. Library and framework developers mostly only know that

Misuse of checked exceptions pre-dates this advice and some of those libraries are very slow to go away. Library and framework developers mostly only know that a client cannot recover from an exception; rarely can they make good judgement about when a client can recover from one but they have to bake that choice in. It's more flexible to encode error or otherwise abnormal returns into the return type - there is basically no reason to prefer a checked exception.