The last one I recall was in Jan/Feb 2021 which I believe led directly to the great arctic outbreak in the Midwest in February (see @Jebman's epic post). Of course that did nothign for the east coast.
SSWEs are enormously complex like most weather phenomena but I have a simple mental model which I think is useful. A SSWE is either going to couple with the troposphere or not. If it doesn't couple, then of course it is useless to us. If it does couple, SOME area of the NH is in for an arctic outbreak, but where exactly that occurs is highly variable as many other have pointed out.
I haven't done any research but based on comments I have seen from the twitterati as well as my own common sense I strongly suspect that the location of any outbreak is not just uniformly random but is influenced by the already existing hemispheric pattern. If so then it makes perfect sense that the SSWE in say 2021 did nothing for us because as we all know our base state has been heavily tilted to SER pattern, essentially acting as a shield discouraging arctic discharge in our neck of the woods.
Given, the different base state this year I think it is entirely reasonable to hope for a higher probability of impact if the SSWE were to occur (and assuming that it couples). So I for one am still hoping for one.