If you have children, you lose out on child benefit between 60k and 70k, which adds an equivalent 10% in that margin.
Between 100 and 120k there is also the loss of personal allowance, which results in a marginal tax rate of 62% in that bracket. If you have children between the ages of 3 and 4, you also lose out on 15 hours/week childcare, resulting in that marginal tax rate hitting 89%
I don’t view paying my own individual debt as a tax. I have a percentage of my pay deducted and diverted to my retirement account. That’s not a tax either, even though it’s percentage-based on my pre-tax amount and directly deducted.
You can opt out of your pension contributions. You can’t opt-out of paying student loans, which is an available option with other debts.
Student loan deductions reduce a balance that doesn’t impact your credit score, can’t chase you for repayment (unless you do something stupid like move country and fail to inform them) and doesn’t impact lender decisions. Most people have no hope of repaying their ‘loan’ in their lifetimes and instead expect the loan to be written off after 25 years. U.K. student loans being debt is a technicality, it’s a tax with a countdown timer that might be shorter if you’re baller.
You aren’t wrong, but hitting 6 figures at age 30 is very far from the typical experience. Outside of London it’s not guaranteed you’d even hit £60k.
Plan 2 students are screwed, with the high interest rates and slower repayment schedule I wouldn’t even be sure non-London devs would finish paying it off.
100k USD in GBP is 73347.60. In the UK you'd be taxed 30% on that, including national insurance. https://listentotaxman.com/73347.60