By year 1500 world population was 500 million, so my point is that your claim how "before industrialization world population was in the lower hundreds of thousands" is completely incorrect. That's my point.

World population by early 19th century was already 1 billion, what are you talking about?

yes, it was.

the first industrialization started in the middle 18th century though, so not sure what your point is.

Probably that already in the "middle 18th century" it was close to a billion people (and in any case, many more than low thousands: hundreds of millions).

Heck, ancient Athens alone (a single Greek city) had a population in the "low thousands" in 500 B.C.

There is no point in the past 2000 years where world population is estimated to be "hundreds of thousands".