At that time there were still people around, active Conservatives, who'd known TR, FDR and the Taft's personally.
BTW, back then we used meeting halls and the mails to communicate ~ worked just as well.
The dichotomy you're talking about as having not occurred until recent times IS WRONG ~
The dichotomy I’m talking about is one of Democratic = liberal/progressive and Republican = conservative.
Until recently both parties had liberal and conservative wings.