The B-36 comes to mind as too big, too complicated, and an easy target for early Russian fighters.
My great-uncle flew on a Peacemaker. “Six (engines) turning and four burning.” Or as some crews said, “two turning, two burning, two smoking, two choking and two more unaccounted for.”
On the subject of economy, the B-36 illustrates the principle that it’s better to have a few really dependable engines than it is to have a lot of questionable ones.