Heres some rough mathematics.
According to the 2018 Grand Total report on JW Org;
2.1 billion hours per year are spent preaching. An average of about 20 hrs per month per publisher. (sounds a bit padded to me).
It requires 7746 hours of preaching per year to create one baptism.
The population of the world increases by about 80 million people per year.
The amount of preaching needed to convert just the population growth each year would be about 59.6 billion hours. About 30 times the current amount.
We know 80 million people per year are never going to become JW's, so thats 80 million people per year that have to die needlessly at armageddon for every year that 'the end' is delayed.