Back in ancient times, scammers placed small ads in the back of comic books and computer ad catalogs and gardening magazines and the like. I remember one case where a guy placed an ad that said, "Send $1 to [his P.O. box]" and made some money over the course of a few months before anyone complained. He didn't promise to send anything for the dollar, so iirc he wasn't prosecuted.
I loved seeing those ads in vintage Archie comics ('60s-'80s editions). Those ads wouldn't bother including a photo, but usually had a nicely drawn artist's rendering. That to me spelled a certain kind of commitment to the scam. Today, all they'd have to do is select the right demographic on FB ads (usually people who "also express interest in" IQ pills or some other snake oil), and click a button to put the text-only ad live.
Maybe add a bad Photoshop image if you're feeling creative.
On the other hand, the Internet makes so many people aware of scams so there is less chance of any particular target falling for it. Of course, some people get so over sensitized to scams that they filter out all legitimate items to thinking it may be a scam.
Scammers also don't need to fool all people some of the time - just some people all of the time. Nigerian Prince Scamming already filters for maximizing gullibility to reduce time wasteage.
Edit: To a degree, yes. Infomercials were wildly successful. But were there other ways?