> Sorry I don't understand "economics."

I would suggest reading this:

https://en.wikipedia.org/wiki/Zero-sum_game#Economics

https://en.wikipedia.org/wiki/Lump_of_labour_fallacy

Paul Graham also has a good article: http://paulgraham.com/wealth.html

There are number of good books on the subject. Tim Harford has some pretty approachable books that are aimed at a general audience. Perhaps others have further suggestions.

As a consideration to others, strongly arguing something you have little understanding of lowers the signal to noise ratio of this site, and might be avoided.

The number of jobs wouldn't remain static. The number of jobs would naturally increase to support the increased density of people. Also, some (hopefully large) fraction of the newly unemployed will find employment elsewhere. Few people get fired from their only job and they say "welp, guess I'm unemployed for life".

Also, 1000 of those jobs are presumably lost because the new workers are willing to work at a lower rate. That leads to two situations:

- The product/service they are creating will be cheaper (e.g. cheaper commodities out of China, cheaper fruit harvesting by migrant workers, etc). The average person spends less of their paycheck on these purchases, which means they obtain more value for less money. Or purchase more things using the same amount of money as before.

- The owner of the business pockets more profit by employing cheaper labor but keeping prices the same. This segues into the idea of "trickle down" or "supply side" economy, where the owner employs more people, expands business, invests more capital etc because they are now spending less on salaries. Not saying I agree with this analysis, but it's at least one viewpoint :)

The 1000 new people also need to buy goods and services, this increases demand, which requires the producers of goods and services to scale up their production and hire more employees.

Money is not a fixed thing, it's debt created by producing something that someone else values. Rather than a personal IOU we all agree to use money as a common means of exchange. Economic health is not the fixed amount of cash that everyone has, but by how many times it changes hands. Poor people who are living paycheck to paycheck are therefore the best contributors to the economy per dollar earned.

Your scenario that 1000 people show up and the jobs remains fixed is nonsensical, the number of jobs is very much correlated to how many people there are. This is somewhat abstracted away by globalization, but it still has to work itself out in the end.