While real life is filled with long lasting wars, it seems canon star wars is far more limiting. Clone Wars, only 3 years. Galactic Civil War cut back to 5 years instead of the war ending 19 years after ANH in Legends. First Order vs NR/Resistence could be even shorter then 5 years with no time jump between TFA and TLJ. With the decanization of the EU we also lost several long running Jedi vs Sith wars, though im gratefully the hundred year darkness survived in some form via reference in a comic. Unfortunately while a war that spans generations such as the 100yr darkness as some good potential, it being set more then 6,000 yrs before the films creates strong uncertainty we will see it soon or ever. I think its likely that Disney doesn't want to take the risk. We could have got a war lasting longer then 10 years in modern star wars if Disney allowed the civil war more time. It didn't have to last as long as it did in Legends, but it should have gone beyond 1 year after RoTJ. Wanting more peace time between RoTJ and TFA im sure had a hand in that decision to limit the war to 5 years. Also because a lot happens in the clone wars and 5yr Civil War, the powers that be still have room for more stories about those 2 significant wars, meaning that they may think a long lasting conflict isn't needed in star wars, because even 3 years can give you a lot of material. So do you believe that if we get another war set after the ST or 1000+ yrs pre-TPM, that for once we see a conflict that is longer then what we have witnessed previously in the new canon? I'm all for seeing a war that goes on longer if Darth Bane's era graces our screen in a future trilogy or tv show. Doesn't have to have roots that go back 1000yrs like Legends did. But have the last war between Jedi vs Sith armies start when Bane was a boy or before he was born. Giving us both the 1st generation of the war who are now old (and many dead), to a younger generation of people who don't remember a peace time galaxy.