Was it easier to develop players with more off season and training camp work?
Yes of course it was.
The teams have adjusted, starters playing little in the pre season.
Practicing against other teams.

My thing has been if you aren’t doing it by year three you can start packing your bags. They all can take multiple year jumps.
Nixon would be a fine example of continuously improving.

Kraft, Williams, Bullard , Morgan, Cooper, Hopper, Valentine , Brooks and Brooks with Reed took or are taking those leaps.

Reps reps reps, those second year, third year jumps come from playing.
Look at the 2nd , 3rd and 4th year starters on the field now.
How many of those earned reps as rookies or second year players?
On this team a lot of them.

The rosters third year players are driving this team and it should with how many there are.
Williams Bullard Cooper Morgan Hopper Melton might all disagree about second year jumps though.
The rookies and second year players are playing a lot a meaningful snaps.