Well, at the level of knowledge you and I have, TINAS, your statement is certainly true. However, high level players like BrokenTree and yaron might be able to know by memorization that really and truly, all the next cards are not helpful to turn the tables.
But to be in such a hopeless state, you almost always have to be 1-2 turns away from losing. I just take a couple draw actions instead of making meaningful choices and let my opponent finish me off, it takes just a few seconds.
If you are resigning because your opponent has 30 in his score pile and has achieved 1, 2, and 3, so actually losing is pretty far away, I would agree with TINAS that you should keep going because there are some crazy luck streaks that can turn things around. Especially in Echoes. I think theoretically Watermill can tech you up to age 10 from 2 in one action.