The problem is if parents are financially illiterates but they don't acknowledge this fact and they believe they are very good with finances, in that case, the children are going to have the same thing, they will be taught things that might be wrong to do or aren't the best things to do when it comes to finances. So, the most important thing is the awareness, they just need to be aware that they lack something and their children must not lack that like them, and they will work it out somehow.
Are you aware of the saying, "You can't give what you don't have? Some parents on their own cannot give their kids financial knowledge because they themselves don't have it, or perhaps they think they are okay the way they are.
Just like you said in the second paragraph, it's only when a parent acknowledges that they are financial illiterate and they don't know how to manage their finances that is only when they can either make sure they provide every possible means to make sure their kids are better, even if it costs them to pay for special classes that their kids will have to learn about financial management. But there are some parents who don't even acknowledge it and therefore don't see it as a necessity for their kids to learn.