Yes, they came out of the box right away very good, but they had Martz. Their success as players were they were 2 of the most savvy route runners in the history of game and fundamentally excellent WRs. They were smart players as well.
All attributes of coaching. While that as a single data point itself doesn't derive the cause and effect, when there is so much overwhelming evidence across the board, you have to conclude that Martz was key in making them great NFL Wrs which by the way, is what he came up in the league as.
Martz was the Rams WR coach in 1995 and 1996.
Bruce was a rookie in 1994 and didn't do a bunch. He had like 272 yards
The next year Martz gets moved to WR coach and Bruce goes to 1781 yards on a bad team. Another one of the greatest spikes in production in NFL history under the tutoring of Mike Martz.
Martz stays WR coach for Bruce one more season and he puts up another 1338 yard season.
Martz leaves and goes to Washington and Bruce's next 2 seasons are:
1997 - 815 yards
1998 - 457 yards and almost skips the end of season team meeting he is so frustrated.
Martz returns in 1999 and his next 3 seasons are:
1165 yards
1471 yards
1106 yards
would Bruce's career that had stalled when Martz left every had gotten back on track? Hard to say? Some of it was health with the hamstrings, but much of it was attitude, approach, fundamentals, mogo, love of game, etc.