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 :)