You could say that SBO, or you could say that the answer is not to try and live in London unless you know you're going to earn a lot. I certainly wouldn't want to live in London if I was earning 35k.
People can spend money however they want. The point (to me anyway) is that if you actually saw your £60/month coffee habit as a bill to pay then you would perhaps make different choices.
"We need this kind of pressure on the millennials because to keep the inflated prices we need people to be able to buy the houses.
Any kind of frivolity needs to be gently demonized- coffee, cinema, takeaways. If they give up then the whole thing falls down!"
You could equally argue that the situation is one engineered by global corporations who have normalised spending habits that would once have seemed frivolous. And that the whole thing would come crashing down if people looked seriously at how they spent their money...