I would disagree that the age of the QB is over, which somewhat implies that you can win without a good QB. The elite QB's regularly opening seasons with 300-yard games were in their primes later in their careers. We have a lot of young QB's in the league right now, and we're comparing it to an era where the top QB's were putting up record breaking numbers in their 30's. Manning was 37 when he threw for 5,477 yards and 55 TD's, and three of Brees' 5,000-yard seasons were at age 32+ (with one at age 37). Brees also had nine seasons with 30+ TD's from age 30-39, but only one from age 23-29.
In 2015, when the elite four of Brees/Brady/Rodgers/Manning were still starting, the average starter age was 29.3, and 15 starters were 30+ years old.
In 2019, the most recent big year for 300+ yard games (13 total), the average starter age was 29.3, and 16 starters were 30+ years old.
In 2024, the average starter age in week one is 27.6, with only seven starters that are 30+ years old.
In time, I think the new class of top QB's will emerge and establish themselves, but they need more time to develop.