adamschic - I don't know where you live, so quite possibly you live in a part of the country where wages are lower but the cost of living is correspondingly lower too.
Your theory that those who are HRT payers are all comfortably off just doesn't apply to those who live - by necessity - down south, in commuting distance to London. For example - my OH's job is London dependent - it could not be done anywhere outside of commuting distance to London. And he's hardly unusual in that. If you look at the cost of housing a family in the south, and transport to work, that eats up a huge amount of salary for all those in that situation; ignoring the obvious fact that AS IT'S TAXED AT A HIGHER RATE, THEY GET LESS OF THE (SMALL) BIT OVER THE HRT THRESHOLD ANYWAY.
According to the tax calculator, someone on 43K takes home £2629/month. OK so far. Start by taking off at least about £1250 of that ie almost 50% on rent and transport to work (I'm assuming on that salary you couldn't afford to buy a family home anywhee near London, unless you were lucky enough to have bought years ago). That wouldn't get you a palace in a posh area or indeed in London itself at all - we're talking a long commute. So nearly 50% gone on housing and essential transport costs already. Add in bills, food - let's hope you don't have any childcare costs because that could eat up the majority of your left-over pay. Obviously, you don';t want holidays or own a car, or ever have any major repairs/replacement costs eg let's say your PC you need for work breaks down. Or someone gets sick.
According to recent figures:
"Rising prices left the average UK family with just £162 of weekly disposable income ? 7.9% less than this time last year."
www.guardian.co.uk/money/2011/sep/27/households-record-fall-disposable-income?INTCMP=ILCNETTXT3487
So these figures make clear that the average family has around £650/month left after paying for accomodation, transport, bills and food. (And that that amount is itself exceptionally low by recent standards.)
But on the figures quoted above, I'd be very surprised if the example family budget quoted above will allow for this. Certainly not if they have any childcare costs, debts or any other unexpected expenditure. DESPITE being supposedly in the top 10%, according to you. Certainly, £600 a month to cover all bills, childcare, and food for a family of 4+ doesn't seem overly generous to me; maybe you succesfully feed your family on beans 7 days a week, I don't know.
So maybe living costs are lower in your area, adamschic. But I would be careful of extrapolating from that to the conclusion that as a result, everyone else in the UK is just ticketyboo, or lying.