Why can vacuum-sealed wet-aging tenderize beef yet usually cost less than dry-aging?

Answer: The seal prevents water evaporation and crust trimming, so more saleable weight remains.

The vacuum blocks tenderizing enzymes, so no costly enzyme step is needed. — Not quite. Wet aging still depends on the meat's own enzymes; the USDA tenderness paper notes that tenderization can occur at the same rate in vacuum-packed subprimals as in dry-aged cuts. The bag does not block those enzymes. It mainly changes the economics by holding in moisture and keeping the surface from drying into a crust that would need trimming.

The bag redistributes intramuscular fat, so cheaper cuts need less time to gain flavor. — No. Marbling is intramuscular fat the animal already had; a vacuum bag cannot add it back or redistribute it into cheaper cuts. Good marbling can make wet- or dry-aged steak more luxurious, but the aging method does not create it. Wet aging is cheaper because the meat stays packaged, so it loses little weight and forms no dried crust.

The seal prevents water evaporation and crust trimming, so more saleable weight remains. ✓ — Right. Vacuum packaging lets the meat's own enzymes tenderize it while blocking the two expensive dry-aging losses: water evaporation and crust trimming. A beef-industry report notes that vacuum packaging grew because avoiding shrinkage and trim loss made economic sense. Wet aging is still real aging; it simply leaves more saleable weight in the bag.