Dry-aged beef is already much tenderer after two weeks, so why do producers keep aging it for weeks longer?

Answer: Flavor keeps developing

Proteins rebuild fibers — Not quite. Aging is mostly breakdown, not rebuilding. Enzymes cut structural proteins into smaller pieces; they do not reassemble fresh muscle fibers in a dead cut of meat. The useful late-stage change is that moisture loss, fat oxidation, protein breakdown, and surface microbes can push the flavor toward nutty, buttery, earthy, or roasted notes.

All bacteria disappear — No. Aging is not sterilization; dry-aging rooms manage microbes rather than making them vanish. In fact, selected surface microbes can be part of the flavor story, while unsafe growth is controlled by cold temperature, humidity, airflow, sanitation, and trimming. The reason to continue beyond early tenderness gains is that flavor chemistry keeps moving.

Flavor keeps developing ✓ — Right. Tenderness improves early, but longer dry aging mainly buys a stronger flavor profile. The dry-aging review notes that the greatest enzyme activity is early and major tenderness gains arrive by about 14 days, while flavor comes from moisture concentration plus protein and fat breakdown. That is why a 45-day steak is not simply 'twice as tender' as a 21-day steak; it is often funkier.