I never said 25,000 people would be from neighbouring companies, just that a non-zero percent would be from the area already. So they aren't going to contribute incremental tax increases.
Most will be replaced, and most of the replacements will also be locally sourced.
Company A creates a “new” job. They hire an employee of Company B, who in turn poaches a replacement from Company C, and so on.
It’s fair to assume that some hires will be new arrivals to NYC, and some might come from the pool of unemployed. Most will have simply hopped from one employer to the next, replacing one job opening with another.
