Yet there are 72 mostly poorer nations above us
I would put it down to the ideology of trying to produce a more conformist and globalist minded population. They need to get back to teaching the basics instead of trying to mind control the kids.
The current syllabus needs to be torn up and they must get rid of the one size fits all approach. We need to teach useful skills such as critical thinking, problem solving, communication, finance, commercial law, how government works, etc.
Most people leave school clueless and are wired to soak up state propaganda via the media and TV. We also need to get rid of the common purpose gatekeepers and anybody else with funny handshakes.
Unfortunately, I can't see any of this happening with Welsh Labour in charge, so education in Wales will probably remain a lost cause.