It was probably easier to get rid the first time than it would be a second time given the increase in air travel and density in population centers that has occurred since then.
Contrast this with polio, where there are about a thousand infections per every paralysis. Thanks to a couple of ignorant leaders who claimed that the polio vaccine is a Western conspiracy to sterilize African girls, it's spreading again. Great.
a) It has no animal reservoirs
b) The latent period of infection is very short
c) There's an effective vaccine
None of those things would be different the second time around, unless the viruses itself was changed.