Neither me nor DH earn £100k but we do live in the south where house prices are ridiculous compared to local wages. There are tiny some tiny new build three bed semis being built in our village right next to a main road with rubbish parking and barely any garden and they want £410k for those 😬
DH could earn £100k if career progresses and we both find it a bit depressing that even if he did earn that kind of money we wouldn't feel 'well off'. After tax and student loans it's about £5k a month to live on. So while that is a lot of money and it's more than we currently live on with both of us working that still means buying a bigger house in our very average village where houses typically cost upwards of £500k will be out of reach.
We would have lost our child benefit, be on the cusp of losing any help with childcare, and losing DH personal allowance looming if he earned anymore.
I think the issue is earning £100k puts you in the very top % of earners in the uk but nowadays won't buy you a top % lifestyle. We wouldn't be sending kids to local private schools, going on nice holidays, buying new cars or able to amass a large amount of savings on that income even if we largely maintained our frugal lifestyle.
The cost of housing in many areas of the country where earning £100k salary is actually achievable means that there's not much disposable income left over.
And that rather makes those who do (or could) earn that think what's the point in working so hard.