Fact-checking was much harder pre-internet. Most people also had no platform beyond their families and friends.
Many media tactics for #politics were developed between the end of WW2 and the US' mass adoption of the internet. Next time you wonder "Why did Politician think we would fall for this?!" it may be because that move worked when folks relied on the local #media outlets and neighborhood rumor mills for information.
It's basically the rhetorical equivalent of running Windows 95.