In the 1960's, ABC seemed to be the "counter culture" to daytime with all the Chuck Barris shows and "Dark Shadows". Acquiring LMAD made it "legit" and probably paved the way for the traditional shows like "Password" to fit comfortably in the schedule. It was as though they stopped programming for the college crowd and more for the homemaker.
There are limitations to that sentiment, in several regards:
1) It feels reductive with quite a bit that ABC aired in daytime pre-LMAD: can we really call
Treasure Isle,
Dream House, or
Wedding Party counter-cultural in any sense, for instance?
2) It exaggerates how rapidly the ABC daytime schedule changed- in part because they programmed fewer hours than the other two networks, there wasn't massive immediate churn, and even some of the new programs don't seem that far removed (some of the short-lived soap operas around 1970, for instance, seem to fit in the efforts ABC had engaged in earlier of having these appeal to a younger audience).
3) Finally, there is an important general context to keep in mind- ABC as a network overall programmed for a younger audience than NBC and CBS did at that time, in an effort to find an audience that could make it something other than the distant third network. It took some time to work overall (in the late 1960s, it was still considerably behind NBC, who in turn weren't that close to CBS), but by the mid-1970s this would pay off, and to a heavy degree this approach to programming is the one that had become dominant with all the broadcast television networks.