We now know this is not the default presentation of Ebola. In most patients, it's a serious febrile disease, not "Leaking blood from everywhere". The diagnostic process is much harder than you're giving credit for.
"I doubt a diagnosis would take more than a day, especially if the patient recently traveled or the hospital is near a major hub. Medical professionals are as obsessed with such diseases as we are."
The number of times travel histories are skipped or missed is staggering.
That being said, I worked in a group that was modeling both Ebola in West Africa and Ebola in the U.S., and the conclusion, even with some pretty serious scenarios, was that Ebola in U.S. would be pretty swiftly contained.
I wouldn't be stunned by a delay in response due to "it can't happen here" chauvinism, but once enough people were taking it seriously I would expect the US public health system to be up to the challenge. Hopefully there would be little or no delay in treating it seriously, I'm just pointing to that as a likely contributor to the size of a potential outbreak.
These all feed and overlap each other. Something can spread through the public school system's children quickly into parents, who take it into large shared office building environments (think typical complex of skyscrapers full of tenant companies sharing hallways, elevators, sidewalks, lunch spots, etc), and once a week completely different insersectional sets of these adults and children then gather up in a large church and disperse into the trifecta.
Hospitals themselves are another factor. Those with family ties end up randomly visiting hospitals a few times a year on average for their eldery relatives' or childrens' sakes, where they pick up a ton of chances at diseases.
I doubt a diagnosis would take more than a day, especially if the patient recently traveled or the hospital is near a major hub. Medical professionals are as obsessed with such diseases as we are.
Once the threat is known, I have no doubt that any decent medical system would contain it within a few days at the most. Ebola isn't the Sci-Fi threat you might think, requiring Biohazard suits etc. Basic precautions work well, finding possible contacts will be much easier, and the tendency of Americans not to attend mass events helps tremendously: Cars instead of public transport, Netflix instead of crowded bars, small families in suburban houses instead of large families in shared apartments, Wall-Mart instead of markets, etc