I stand corrected. The first study you link is pretty new.

An excerpt"

"At a dose of 150 μg/kg, observation of 52 patients on mechanical ventilation appeared to show clinical benefit with the drug in contrast to over 1,900 patients on conventional treatment. Though these results need to be analyzed to rule out confounding factors and biases, on the surface, they would seem to suggest that very low lung concentrations of ivermectin are able to inhibit the virus.

In other words, even when the ivermectin concentration is not anywhere near the IC50, it appears to have antiviral activity. This could suggest that the lung distribution or accumulation of this drug is far greater in humans than in cattle.

In contrast, the concentrations of ivermectin reported inhibiting the coronavirus in vitro were markedly higher than those achieved in human lung or plasma with the approved doses of ivermectin. As a result, say the researchers, “the likelihood of a successful clinical trial using the approved dose of ivermectin is low.”

This should be a warning to conduct in vitro studies of repurposed drugs at concentrations that are safe and tolerable in humans."

Waiting till the patient is on mechanical ventilation than giving them a single dose is not going to do much. What did they expect? At mechanical ventilation the virus has long since quit being the problem. It is the body's response to the viral remnants that are the problem. Any help from ivermectin at that point is as an anti-inflamatory, not an anti viral.

Then this:

It has come to our attention that the original title of this article, "Ivermectin alone not useful in treating COVID-19" was inadvertently misleading. The title has been corrected to better reflect the research paper's title, "The Approved Dose of Ivermectin Alone is not the Ideal Dose for the Treatment of COVID-19".

They put out a headline (knowing many people will not actually read the article), then correct it later. It does not say ivermectin does not work at all. It says more work needs to be done on dosing.