And this is where the crux lies: you'll get paid better for your work in London, but unless you become truly rich, you'll still not earn enough to afford your own roof over your head. All your money will go on transport, rent and living expenses. The amenities afforded by a city, restaurants, cinemas, etc - these all cost money and are more expensive than outside of London. So you end up paying through the nose for the reasons why you actually moved to the city.
So you do the grind for 10 years, say you are actually quite good and have a bit of luck and you are now earning 5x the salary you could earn in some bumfuck village in the country, but you still can't afford to own anything, you are permanently feeding rent seekers on everything. Once this realisation hits, it's difficult to care about doing a good job. You realize that you could do a shit job, put the minimum effort and still get 80% of your "peak" salary, and this marginal decrease won't affect you in any material way. Perhaps you have to cut back on eating out, or maybe lease a 2 year old car instead of a brand new one. But you realize that this marginal 20% increase in salary won't get you anything that'd be worth all the extra stress coming from caring about your job.
You'd need to sacrifice all your social life, your energy and free time, put in a hardcore grind, save every last penny you can, and then after 10-15 years you can buy a tiny rowhouse on a mortgage with a postage stamp sized garden - if you are lucky. And then you realize you spent the prime years of your young adulthood but instead of a landlord you are now beholden to a bank and an interest rate. You are terminally burnt out and haven't been able to properly enjoy life in any way up till now, and the grind isn't over. Instead of paying rent, you now have to fund the mortgage payments for another 10-20 years.
Even if millions of Londoners hate it that doesn’t change the fact that they are continuing to do so day after day… so something must still outweigh all the downsides combined.
So their care is very high, just focused on perhaps a very peculiar basket of things, so to speak. I can’t see any other explanation for such large scale behavior.
They still feel better off than doing a shit job in the countryside, otherwise they'd move there. But the question we are discussing is: "Why don't people care about doing a good job?"
I don’t see how one relates to the other, I wasn’t questioning the latter point? It’s undoubtedly the case for many.