Yes, but keep in mind that while the health authorities (CDC, WHO, etc) may keep track of individual flu strains spreading from place to place, most average citizens don't pay any attention to that. Similarly, if a known illness is present in far apart locations, say, China and the USA, a person traveling from one to the other can be a vector to infect someone in his destination and we'd never know (or blame him for it) because it's already in both places.
In other words existing illnesses probably spread from continent to continent just as easily and rapidly, we just don't pay attention to it because it's already in both places. The only reason we are noticing the spread of COVID across continents right now is because it's relatively unique and we are paying attention to it. I bet if we tried (or had the ability) to map individual flu infection vectors on a global scale, it would appear to be a very similar rapid spread across continents. China -> US -> Italy -> Iran -> China and so on.
As far as cruise ships and nursing homes - kind of the same thing. Lots of diseases already spread on cruise ships and nursing homes because they are relatively confined and captive spaces with dense populations for extended periods of time sharing toilets and dining facilities. People have been advised to wash their hands on cruise ships for a long time predating COVID.
None of this is meant to disagree with your point about it being contagious, just saying that the anecdotal data we have right now about how it spreads doesn't necessarily mean it's super contagious because all diseases spread similarly to the maps and anecdotes we've heard so far. The stuff about "can be present on surfaces for 7 days" and "14 day incubation" is much more indicative IMO.