And if you think Lemond Hinault, etc. didn't care about intervals, power, numbers, etc. you should read this interview with Lemond http://bikeraceinfo.com/oralhistory/lemond.html

Training by power, periodization, and the like are relatively modern concepts, but they have pretty much always done something like intervals in some form. Rather than going as hard as you can all the time, you go harder than you can go all the time, for a short period of time. Eventually you can do that intensity for longer, and even more intensity for a shorter period of time. They just didn't quantify it, label it, and package it like we do today.