So, the YOU here doesn't always relate to the listener/reader, right?

Right, it’s the general YOU. Someone claimed that children always make their parents happy, and this person is disagreeing, but stating that it would be a good thing if it were true.

We say I WISH when we mean “that would be nice/ideal, but that’s not the case.”
— Is that your new Mercedes parked in front of the house?
— I wish. It’s my brother’s.

Just one thing: "Wish you WERE here" - why not "children MADE...? Or is it a fixed construction here, with the Present Simple?

Because the speaker is echoing something someone just said:
A: At the end of the day, I’m just so grateful for my kids. Your children always make you happy.
B: I wish “your children always make you happy.” I have two in jail and one on the corner. Speak for yourself!

Or maybe this is Alex trying to say “I HOPE your children always make you happy.”!

Oh, gosh! Who could guess! 😅

Who could’ve guessed! -or- Who would’ve thought/thunk it!

Oops!

😉

I took it from here:
Now who could guess or who could possibly know
That this same man named Kennedy

Would be the leader of the nation, be the one to take command?
The P.T. 109 was gone but Kennedy lived to fight again

That means AT THAT TIME IN THE PAST, nobody WAS ABLE to guess. COULD is the simple past of CAN.

Yes, yes, yes... 😀

👍🏼🤩

As you know, my head is stuffed with lots of pieces of lyrics which I even managed to dig out on my first telecons with the US counterparts. And it worked!))

I know. And that’s a good basis!

Uly, could you explain, please: 'Thunk' - is it normal to use it instead of 'thought'? It's the first time I've come across it.

It’s very common, but humorous. The speaker is making themself sound oblivious or silly for not noticing or knowing something.

Thanks, Uly, that's an interesting nuance.

Yep 👍🏼

Это типа "А я-то не сообразимши!"

Спасибо

I HOPE your children always make you happy.