Idk about the record breaking defense thing. I kinda think the strength of this team may end up being pass defense/pass rushing, so playing teams that throw might balance that out a bit.
But I can kinda see what he's getting at about development. If it's not development, then at the very least the staff has not done a great job taking advantage of the talent and athleticism on the roster. In week one we've already seen two examples of guys (Bituli and Callaway) who are obvious playmakers who would've been buried on the depth chart if not for injuries. We've seen similar things in the past (Devrin Young over Berry at KR, Jumper over Kirkland, Hurd over Kamara, Dobbs being buried on the depth chart).
So idk. Part of me worries about development. We basically only had 6 DL ready to go for week one. Not getting a bit more out of guys like Alexis Johnson at DT is concerning. You'd hope they'd have guys like Deandre Johnson and Matt Butler far enough along to contribute 10-15 snaps out of nearly 100. Ja'Quain Blakely looks like he might be destined to be a career long punt protector. Jack Jones has as much upside as anybody not named Trey Smith on our OL and he was very fundamentally unsound Monday.
I think it's not terribly unfair to look at some spots on the roster and ask why we haven't gotten a bit more out of them. Maybe it's more about risk aversion than development, idk. But it will be a question mark until we see some current starters take a step forward and some depth guys start to make meaningful contributions.