When you're on 100k and things are tight, you can cut back in more ways (don't have that luxury holiday etc)
Again this will depend on circumstances though. Clearly there are plenty of 100k earners who have all sorts of luxuries, but they don't all. As I said upthread, if you're paying SE housing, commuting and childcare costs, I can see how there wouldn't be loads left at the end of the month, especially if you have debts too.
My hypothetical London couple earn 60k and 40k working full time, and have two kids. Student loan repayments, 5% pension. 60k brings home £3050 a month, 40k £2030. No CB or TCs. That's a monthly income of £5100. Let's say housing is £1700, council tax £150, 2 commutes is £250 and the childcare for two preschoolers is £2000 a month (could be a lot more but let's assume some vouchers). That's £4100 already, before anyone eats anything, heats anything, wears anything or washes anything. Now clearly there are loads of 100k earners who won't have anything like these expenses, and clearly there are also lots of people who don't have 1k a month for food, electricity, gas, non-commute transport, water, phones, clothes, insurance and entertainment.
However, that is not luxury holiday money either. Especially not if our couple have any debts. I agree that there is still likely to be wiggle room in a way that there's not when you're on the breadline. The 100k couple probably get a few takeaways and new tops and a cheap week away in the summer. Equally though, my family, also contains two small children and two working parents. We have quite a bit more left over than my example couple after housing, commute, childcare and council tax even with less than half the household income.