Many days and years - rather, “In little more than a year” [Maurer]; literally, “days upon a year” (so Isa 29:1).
vintage shall fail - through the arrival of the Assyrian invader. As the wheat harvest is omitted, Isaiah must look for the invasion in the summer or autumn of 714 b.c., when the wheat would have been secured already, and the later fruit “gathering,” and vintage would be still in danger.