It can’t last, can it?

Offenses have been the marketable face of the NFL for four decades, since the league approved two significant rules changes in 1978 to increase scoring and excitement.

The first was to allow offensive linemen to extend their arms and grab defenders, which helped protect quarterbacks and gave them more time to throw. The second was reducing from 10 yards to 5 yards the “chuck” rule that defensive backs could use to contact receivers, thus giving the receivers more room to run free.

In 1978, only one team averaged more than 24 points a game — the Dallas Cowboys. The following year, there were three, led by the Steelers (26 ppg.) As offenses took advantage of the rule changes, scoring increased just about every season. Last year, 13 teams averaged more than 24 points a game, second most in a single season since 1978.

That’s why any number that appears to favor the defense — as Week 1 did — is considered an anomaly, if not a rarity.

“If you want to be a good offense, you have to be able to handle it,” Roethlisberger said. “When we come to OTAs and minicamp, that first day we always expect the defense to win. Always. We want to win but we expect them to because they have more stuff they can throw at an offense. And if you’ve never seen it and you might not pick it up.”

That might explain the number of sacks in Week 1, the most on opening weekend since there were 81 in 2013. It might also point up the number of bad offensive lines in the league. The Vikings, for example, were so upset with the amount of pressure Bradford endured last season they rebuilt their entire offensive line in the offseason and will have five new starters against the Steelers.

The Steelers don’t have that problem. They have resigned every starter on what is arguably the best offensive line in the league. Roethlisberger, who was sacked just once against the Browns, has been sacked just seven times in his past nine regular-season games.

“You can say the defenses are ahead [of the offenses] because they got a lot more rotations, they can rotate more players,” said All-Pro center Maurkice Pouncey. “The offensive line is just fullgo every single play. We’ve been that way our whole entire life.”