Dude, none of your economic analysis makes any sense. I mean, you say "A £65,000 job has a lot more expectations than a £45-55k job." Welcome to reality. Yes, the amount only above the band cutoff will be taxed at a higher rate. For you, it may not be worth it. And that's fine, lots of people are cool with lower stress for less money. But obviously for a lot of people it is worth it.
All you've done is describe the tradeoffs in whether working harder is worth the extra money to you.
Yes it does if you understand the context. We are comparing having similar tariffs with 0% income tax to the current situation which is income tax and some Tariffs.
If the income tax didn't exist at all, I would keep all of the £65,000 and it would be totally worth working those hours. The extra £13-16k a year would allow me to pay off my current apartment in 3-5 years, not 10-15 and then I could get a lower paying job anyway and work less sooner. So the trade off IMO would be totally worth it.
All you've done is describe the tradeoffs in whether working harder is worth the extra money to you.