I went to a school in a northern town where most of the white kids left at 16 and some before. The white kids who stayed on in 6th form were mainly from European backgrounds.
There wasn't any interest in further education because that involved too much hard work. So they all went in to manual labour and minimal wage jobs and the poverty trap. Their families were similar and actively discouraged education and didn't make the connection between education and higher paid jobs.
I didn't have an option but to go to university, my parents made it very clear that's what was expected. It was a similar experience for many friends in my immigrant community. Mainly because regular jobs weren't open to us due to racism and discrimination. I couldn't get a Saturday job in retail during the 80s because my face didn't fit.
So all my efforts were spent on getting a degree, moving out & getting a professional job. More options were open to me this way, even though it was still hard. The w/c white kids could walk into jobs in garages/ factories/shops where their families worked. So they had access to another 'jobs for the boys' network that I didn't.
Kids from immigrant communities generally didn't have that option. We could get jobs in restaurants/takeaways while we were at uni/training but they were only temporary. The expectation was always to move out of those jobs and into professional jobs because working conditions were better.
So now you have a situation where the Indian restaurant trade in the UK is struggling to recruit UK born staff. This is because the 2nd/3rd generation kids don't want to do it. Their parents have generally moved away from that industry so immigrant staff fill the catering roles now. This is just one example of the impact of higher education in the Asian community.
My rambling answer hasn't completely answered your q as to why white wc boys aren't thriving. However, it provides a bit of background as to why the Asian community has instead.