Looking at scores from around the country, both high school and college, it seems points are down pretty much across the board. Perhaps the trend began with 2023 Michigan, which won a title primarily by being stout on defense and workmanlike on offense. It continued last year. The teams who played in the national title game played several games with modest point totals: OSU losing 13-10 to Michigan and only managed 28 points vs. Texas beacuse of a "strip six" to close out the game. Notre Dame lost 16-14 to Northern Illinois and never scored more than 27 points in any of its playoff games. This season started with some notable scores including Ohio State winning 14-7 over Texas and LSU winning 17-10 over Clemson. Across the board, there seems to be much fewer "shootout" type scores than in fairly recent times.

Are defenses catching up to offenses, which seem to be less diverse in style of play from team to team than in the past? I often feel like I'm watching the same offense every game regardless of the name on the jerseys. No matter how good the scheme is, if everyone runs it for several years, it's easier for defenses to be prepared.

 An alternative explanation might be the insane amount of roster turnover we now see. Offense requires more cohesion, timing and rhythm than defense. All of the moving parts teams deal with out of the transfer portal might make things more difficult for offenses.

I don't know about that.
The Texas/Ohio State game was very dull and;very conservative.
One team played scared and the other was glad of it.

LSU's offense played well enough to put over 30 points on Clemson, but they didn't"t.

That said.
A lot of coaches at big-time programs still try to establish the run and running the ball against these mammoth DL's and LBs these days is pretty tough.

Alabama who loves to pound the rock only had 80 yards against Florida State rushing, but they kept trying and wasting a lot of plays.