The defense isn't good enough to bail out the pitching. The pitching isn't good enough to overcome defensive lapses or bad calls. Even a missed scoring opportunity plants defeatist seeds.
So long as everything goes smoothly Paddack, Ober, Sim et. al. can be productive. But one blunder and the wheels come off. At least they have short memories and come out and can throw productive outs and innings but the damage is done ..