I'm in favour of children studying more subjects, for longer times. I think English-speaking countries short-change their children - and by extension their citizens in general - by expecting so little of them while they're at school and so leaving them mostly poorly educated.
(Of course many people don't realise how ill-educated they are. Why so? - Left as an exercise ...)
I'm a product of UK education, A-levels, university, postgrad etc. Very narrowly educated at school, filled some gaps in later years ...
My children, by contrast, outside UK where we stayed for all their schooling, studied three sciences, maths, history, geography, philosophy, art, music, four languages, sport, until age 18. Then they went to UK universities to study different STEM subjects, where they found to their surprise they trod water at first while their British peers with much-vaunted A-levels (gold standard!) caught up with them. Some of them went elsewhere in Europe for a year with Erasmus etc., studied in other languages (physics in Spain for instance). And so on.
Now each of my children has a STEM doctorate and a variously interesting career. And they still speak lots of languages, can quote Shakespeare, Molière, Goethe etc. in the original, and are aware of (particularly but not exclusively European) history and geography. They also play different musical instruments - in the past in various orchestras/bands - sing in choirs, and teach their children to paint, draw and sculpt.
Reading this, you probably think I'm making it up, or that my children were/are exceptionally talented. Neither is true. OK, me and partner are middle class, relatively well-off, concerned with educating our children well back in the day. Involved. That helps, of course. But ...
Of course I think highly of my kids, like any parent. But really they were never exceptionally bright, although they did study exceptionally hard as adolescents. Also, they had good teachers, well-qualified (and well-paid!).
My point is that any child of average or above talent and intelligence can do this. But we don't ask them to. It would take resources - financial and otherwise - we are not prepared to offer.
Anyway, so overall I support Rishi S and others who wish to do more with children in post-16 education. (That's not enough to get me to vote Tory, but never mind. Another story, OT here really.)
[Oh, and as for the state/private divide in British education: ... Ugh! And those of you who see public schools (private schools) as offering anything decent: think again. Eton and co. are awful - just look at their alumni: ill-educated in a different way. Awful. But that's a different matter, also OT.]