The bother with this argument is that the people who come later are revisionist historians. They rewrite their own history to suit their preferred present needs.
Did the Bible Students in the days of Pastor Russell believe he was the F&DS, yes.
Proclaimers Book, jv 18, p625: "Many who were sifted out at that time clung to the view that a single individual, Charles Taze Russell, was the “faithful and wise servant” foretold by Jesus at Matthew 24:45-47 (KJ), which servant would distribute spiritual food to the household of faith. Particularly following his death, The Watch Tower itself set forth this view for a number of years. In view of the prominent role that Brother Russell had played, it appeared to the Bible Students of that time that this was the case. He did not personally promote the idea, but he did acknowledge the apparent reasonableness of the arguments of those who favored it."
But now poor Bro Russell has been relegated to a John the Baptist role, a forerunner of the true faithful and discreet slave class. Says who? Why the present F&DS of course. In much the same way that they now apply more to themselves only and not to the global anointed ones. Because now they teach that the faithful slave only came into existence in 1919 C.E. (Watchtower February 2017, page 25, para 10.)
Revisionist historians. Chop and change the facts to suit themselves. And the rank and file just gobble it up.