system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 - how are western economies sustainable?

I live in the uk, but the more I think about it, the more I realise that it just seems to be series of office workers propping up each others salaries. There’s no (or small) base that actually produces goods, the farmers or the labourers as such. Why?
gpt
Modern and wealthy economies tend towards being service based (it is one of their defining characteristics. Think about a typical "wealthy" society - just the basics but it can be extrapolated

1) Food - how many times have you encountered dysentery? Food containing things that will kill you in days/weeks? How about malnutrition? Where does the infrastructure for food safety and distribution come from?

2) Healthcare - We expect specialist care, modern and available treatment. Something like COVID-19 spreading even 150 years ago would have multiple times more death. Few people die from treatable diseases and many more diseases have become temporary inconveniences rather than a death sentence. If we fall and break an arm or leg, we don't expect that there is much chance of amputation or death through sepsis - yet that wasn't the case just a few hundred years ago.

3) Education. Where does the infrastructure to support specialist training, the basic education needed, all those things we take for granted. Basic education and literacy being universal, etc are all fairly modern. Just go to less developed countries - this kind of thing doesn't come automatically. Scientific research, technological progress can only take place within a society that has the resources to foster education from the bottom up. 

4) Safety - How many people die in factories and workplaces? How many have their health and lifespan destroyed by their working environment? Contrast this to poorer nations. How are these regulations enforced? How are these improvements put in place? The legal framework and enforcement mechanisms, inspections, licensing, etc are there for a reason. 

Entertainment, transportation, communication, finance etc etc. The modern economy is complex and delivers a standard of living for the average person that not even kings of 200 years ago could experience. If 80% of the people are working the land or engaged in primary production, there is zero chance that there would be enough leftover labor and resources to deliver these outcomes to the average person.