Sorry I have to eat crow. My picture from the OP says generation THAT SAW 1914. So that in itself does not encompass an overlapping generation. But I wasn't talking out my ass, I just remembered a different quote.
The January 1, 1989 Watchtower clearly pointed to the year 2000 as the farthest limit of the preaching work and our system of things. It stated, "The apostle Paul was spearheading the Christian missionary activity. He was also laying a foundation for a work that would be completed in our 20th century."