^So a 2 person household of 2 average earners in an average area is earning £65-70k between them, so £4,200 per month after tax.
That's quite a bit compared to the odd £50 here and there^
I find it hard to believe that the average monthly household income is £4200 pm, especially as many households do not have 2 x full time workers, but if that's what the stats show?
But you can't really compare 'the odd £50' against the whole £4200, because you first have to remove all fixed costs for housing, bills, transport, childcare, replacement of cars, white goods, etc etc to see how the cost of eating and drinking out fits in with disposable income.
That's what people have to decide against, is it worth spending £50 for the experience? Some will think it's worth it, some won't. Most people only have so much disposable income, so if they spent £100 a week on a couple of 'proper' nights out, they wouldn't be able to afford to go on holiday or something else that might be similarly important to them, or even more significant, it might leave them short of essentials or falling into debt.
I personally don't mind the spend occasionally, maybe a few times a year, but I'm never going to be out for 'dinner and cocktails' every week, because the cost isn't really worth it to me.