Right, "until recently."
A lecture consisted of a professor reading a book to a class full of students who hurriedly made copies of it in real time, like an in-person bit torrent. That gradually evolved into people lecturing about the subject, but it's still basically graduate-level storytime.
So why are we still doing it when books are (mostly) cheap, and information is freely available on the internet? Even back in the 1500s, people thought the printing press spelled the end of lecturing, but it persists today, so it must be the best way to learn, right?
"Yup, don't change anything," says the kid watching porn on his phone.
A good deal of research has gone into more active learning approaches, and it found that they may be more effective and require less background knowledge to learn the same material. (In fact, some studies have shown no method of teaching is less effective than lecturing "including, in some cases, no teaching at all.") That doesn't mean "teaching" is an elaborate scam or anything -- just that maybe, on the structural level, kindergarten has it more together than your sophomore survey class.