Whatever you all think the Adam Smith agenda is, I'm still not seeing you engage with the contents.
Good for you being a high earner who likes your job. There's diversity among people's motivations for work. It doesn't take many people "simply working for the school fees" to stop doing so before the economic rationale for this tax is destroyed.
"Why is it relevant that lots of people work hard without earning high salaries? Simply because it is quite offensive when high earners bang on about how hard they work, seemingly oblivious to the fact that there is no direct correlation between high earnings and hard work. It might be obvious but it bears repeating."
And for the millionth time, other people's challenges aren't relevant in microeconomics. Nobody said the hard work of private school parents is unique and I don't know why you imagine anyone did. What I've said is the hard work of higher earners paying school fees is very easily withdrawn, and if it's withdrawn it has an economic and fiscal impact, and that impact is no good to anyone, least of all the poor.
And as for your logic that you are paying the salaries of private school staff, and therefore their taxes...where does that end? Arguably, that means that you're not actually paying for your children's education at all, it is the people who pay your salary that are ultimately funding it. Or perhaps the people who pay their' salaries?^
You're absolutely right. When we do economic activity we support other economic activity. My employer pays me to do stuff that's valuable; that pays the school fees; that pays for the teachers and support staff; that pays a heap of tax and supports a downstream economy that pays a heap of tax. Any break in the chain affects the people upstream and downstream, which has economic and fiscal impact, and that impact is no good to anyone, least of all the poor.