I don’t think British people hate success, we just hate unearned success.
We actually celebrate success all the time, just look at tv shows like great British bake off and pop idol. Look at our worship of footballers.
When we know that success has been earned through talent or graft and is therefore aspirational, we are on board! Unfortunately, a lot of people who are succcessful in this country did not earn that success - their wins were borne of privilege (the creation of an uneven playing field, through legal, economic and political structures developed and upheld to maintain the status quo) and removing the potential for success from those more deserving.
This is why private schooling is so hated. It is the absolute epitome of an uneven playing field created through legal, economic and political structures. People, usually through inherited wealth, and helped along by a legal and economic system that makes it possible, are able to pay for their children to opt out of meritocracy and gain the contacts and social capital that will get them ahead of any peers who are just as bright (if not more), capable and hard working. In doing so, opportunities are removed from those lower down the social strata. Private school inhibits meritocracy and fairness. This is bad for our country in multiple ways. Firstly, because it means people are promoted beyond their competence, so our country misses out on vital skills, and secondly because the top jobs (politics, medicine, the arts) are dominated by an unrepresentative section of society who make laws, art and other decisions that impact on our lives.
I see a lot of Schroedinger’s private education apologists on here (for want of a better phrase)! People claim that private school education doesn’t matter because those who are smart/ hardworking will rise to the top anyway. Those same people send their kids to private school. Why? Because they know they can buy their way ahead and skip over those who would otherwise rise to the top.