Did people know Krishna before He appeared?

Krishna says yogo nastah parantapa, “The spiritual science has been lost.” The fact that at a particular place, at a particular time, people forget something does not mean that it is not true. Krishna clearly said, “I spoke this to Vivasvan.” He also says, “I spoke this before but it was lost.” Even after Vyasa divided the Veda and did all of his work, still he was depressed because he had not given the real point. Narada Muni came to him and explained the point about Krishna. This means that, according to the Bhagavatam, the literature that existed at that time in India, the four Vedas and all the other literature, did not have the highest truth. That is why Vedavyasa was unhappy. That is why Narada came to him. According to what Krishna says and according to what the Bhagavatam says, we would expect to find a situation in India when they did not know Krishna. That is what we would expect to find based on what Krishna says.