nah, we've had the 80-year war and the 100-year war.Personally I feel that it's a miracle the Ancients lasted as long as they did.
A hundred years of war is longer than any war I'm aware of in Human history
well it's a matter of how hard a blow really hits.Yes the Ancients had different kinds of technologies, but the Wraith apparently had a moving, expanding industry that could be expanded on any world and at will by the Wraith.
That's a pretty hard thing to fight.
every blow on the Ancient industrial machine would've been a heavy one. Since the wraith make their stuff from the most abundant of materials, every blow to them would be marginal: every world they loose is a world they can easily replace. every ship they loose is even a potential source for new material. they require no complex systems to build their stuff, manage their stuff, etc.
the wraith are flexible. the Ancients are not.
my personal thought is this: the Wraith managed to destroy the Ancient drone and ZPM factories, leading to a massive shortage of them. it led to a vast decrease of effectiveness for the Ancients, untill they more and more began to ran out of drones.
since sheppard says "They could win almost every battle but not the war", it suggests that when the wraith struck a blow, it was one the Ancients could not recover from.
as to the wraith: it seems that the Wraith never really maintained their fleet. in Allies, there's a remark to that. what we see now, is a fleet of ships that's a ghost of it's former self. besides, Hives aren't even fit as warships.