Minimalist wrote:Why do you suppose that is?
Four reasons come to mind, min.
The first is NASA's David Morrison's early impact hazard estimates, which set the cometary impact hazard at near zero. Morrison formed his estimate based on crater data from the Moon, conveniently forgetting the Moon's nearby large companion, the Earth.
Morrison was a reviewer, and active with septical groups, so when comet and comet fragment impacts were researched, he did his best to stop it, as it conflicted with his "data". In sum, Morrison mistook his analysis for data.
Morrison's low estimates of the impact hazard fit well with NASA's institutional desires, which were and are largely wrapped up with fantasies of an Earth-like Mars and manned flight to Mars. NASA actually viewed and views dealing with the impact hazard as something of a diversion from this.
Third, institutionally, archaeologists have trouble working with a new significant natural phenomenon which they had not worked with before, largely because nothing hit Europe in the last 900 years or so.
Fourth, there is the factor of the psychology of denial. We have seen the devices used to grasp at straws here, and generally, if one examines the response to the Holocene Start Impact Event, one will see the same mechanisms at work.
There are a number of minor factors which I will omit mentioning to keep the focus on the larger factors involved.
What will break this feedback cycle is undeniable geological evidence of recent impacts, which is on its way.