There's a right mix.
Some people do completely adult-led, curriculum-based quasi-school schooling. that suits some families.
Some people do a mixture of adult-led formal learning and more free-flowing just-living-life. That suits some families.
Some people just do the free-flowing approach. That suits some families
Let me tell you how the last one works, because that's what I live:
If I went to the library with my children, I'd just invite them to have an explore, read some books that interest them, maybe take some books home. If those books led to conversations about some topic, then I'd make sure I paid attention to those conversations, answered their questions honestly, kept the conversation going until they were ready to leave it. If the books led to imaginative play, fine, I'd leave them to it. If they wanted to look things up on the internet, I'd leave them to it if they are experienced with google, and answer questions when wanted "Mum!! Read this NOW!!!" Or I'd be there advising if they aren't internet savvy. If they wanted to draw or paint, I'd get the materials out for them.
For me, it's about facilitating, not pushing my agenda. They'll be learning all the time, and the things they learn because they are motivated to are going to STICK in a way that your Titanic project just won't, because it's your agenda not theirs. I mean, they might acquiesce and go along with the Titanic idea, but following their own ideas will be much more intellectually productive.
And they might not produce any sort of educational "product" for weeks on end - and that's fine too! No writing, no paintings. But when they really WANT to write, they will.