Can someone explain how anything survived this Chicxulub impact theory of m extinction?

The asteroid impact theory of m extinction is one of the biggest myths in science. If there were an instantaneous annihilation of life, there would be a worlwide "bone pile"; there isn't one. There is a worldwide clay layer, supporting the impact but no indication of mive loss of life at an instant in time. There were other factors at play at the time, much more gradual ones, which are being researched at this time.