This may all be true, but it does not say anything useful about Ebola and what the selection pressure it is under. At the moment the speed of disease progression to death is so fast that it is slowing the spread of Ebola. If the Ebola took longer to kill it would infect more people.
The problem with Ebola is its mechanism of transmission is quite closely linked to the reason it is lethal (large virus production and body fluid leakage). It would take a very large leap in genome space (mutations) to turn Ebola into a virus that is efficiently transmitted, but causes limited symptoms like a Rhinovirus. It is not a large jump in genome space for it to just become slower in progression.
The problem with Ebola is its mechanism of transmission is quite closely linked to the reason it is lethal (large virus production and body fluid leakage). It would take a very large leap in genome space (mutations) to turn Ebola into a virus that is efficiently transmitted, but causes limited symptoms like a Rhinovirus. It is not a large jump in genome space for it to just become slower in progression.