Not to put too fine a point on it, but Lake Missoula is/was small potatoes in the overall scheme of things. If memory serves, he had no small amount of difficulty in getting his work recognized before it was finally "published". After all, he was committing heresy against the conventional wisdom even then.
And without concept of tectonics, it's no wonder.
Again, if memory serves, plate tectonics; that is, the GRADUAL sliding of the plates over and under each other was adopted as an explanation for mountain building etc over gazillions of years. Sharp peaks and ridges would have long ago been reduced to rubble under the theory. Plate tectonics can't explain many of the geologic features we see today without sudden and massive movement -- which the accepted paradigm doesn't allow.