We have far fewer people than growth rate at the time suggested; IIRC, around that time growth was viewed as exponential with a doubling period of ~35 years, had it continued the population would be 10.74 bn now, nearly 1.5× what it.
So, no, population (at least high population) isn't something that was unforeseen.
...and the fact we have about 4bn more people here than we did in 1960.