The death of the indirect question

Why is it that so few native speakers of English know how to form an indirect question these days? I have to teach this point to foreigners and they can do it. I mentioned this on The Guardian website recently and a non-native speaker thanked me, because they had learnt English at school and the person was wondering whether he or she had learnt it incorrectly.

What am I on about? 

Earlier this month, I was looking at a cartoon strip by an Australian artist (First Dog on the Moon) https://www.theguardian.com/commentisfree/2021/feb/05/how-did-we-find-things-out-before-google-remember-going-to-the-library#comments).

In the second frame, there is the following question: "Can you tell me when is bin night?"

Totally wrong. 

A direct question relies on inversion to show it is a question and not a statement: "When is bin night?" See? The 'is' comes before 'bin night'. "Bin night is Thursday." "When is bin night?" Easy.

An indirect question starts off with a phrase that makes it clear that what is being said is a question:

"Do you (happen to) know....when bin night is?"
"Could/Can you tell me.....when bin night is?"
"Would you be so kind as to tell me....when bin night is?"

The introductory phrase is the question bit and what comes after it keeps the same word order as in a statement.

Statement: He reads thrillers.
Direct question: What kind of books does he read?
Indirect question: Do you know what kind of books he reads?

Statement: The train leaves at 12.
Direct question: When does the train leave?
Indirect question: Do you happen to know when the train leaves?

English is a Germanic language and this point of grammar is the same in German, too.

Statement:            He is here.                                       Er ist hier.
Direct question:     Where is he?                                   Wo ist er?
Indirect question:   Please tell me where he is.             Bitte sag mir, wo er ist.

And yet so many people in the UK can't seem to make an indirect question, whether they're on BBC radio, on TV or writing for newspapers. It's almost a miracle when you hear someone actually make a correct indirect question. I've heard it twice in the last two weeks, and I listen to the radio constantly.

I always think that if they can't get the grammar of their own native language right, what else can't they get right? Facts?