Again, I see that said a lot "why don't we win more games considering all of the talent we put in the NFL". But I think this is pretty easily explained. I am not sticking up for Ferentz, so much as trying to show that the NFL numbers pretty much add up to what Iowa has been and is currently as a program.
I pulled the numbers below (it is as of September when the 53 man rosters were released, so likely varies a little as of now but you get the idea).
RANK FBS SCHOOL PLAYERS
1 Alabama 44
2 LSU 40
3 Florida 38
4 Miami 36
4 Ohio State 36
6 Florida State 33
7 Southern Cal 32
8 Clemson 29
9 Auburn 28
9 Georgia 28
11 Stanford 27
11 UCLA 27
11 Tennessee 27
14 Michigan 26
14 Notre Dame 26
16 Iowa 25
17 Texas 24
17 Penn State 24
17 Texas A&M 24
20 Oklahoma 23
21 Wisconsin 22
21 California 22
21 Washington 22
21 Mississippi 22
21 South Carolina 22
Iowa comes in at #16 on the list. I think it can be argued that at this point and over the last 6 years (which is pretty relevant to who is in the NFL right now), that is about where Iowa has been nationally. Overall, they are a 15 - 30 type program (yes I know can talk about finishing in Top 25 and whatever) and a 51-27 record the past 6 seasons comes out to an 8.5 - 4.5 record.
Also, a lot of the players that Iowa has in the NFL tend to be OL, TE, DL, LB. Besides the CB's they have, most of them are not "skill players" and I think that can be attributed as to why Iowa is an 8.5 game a year winner and not a 10 game a year winner (and thus a Top 10 program). In addition, a lot of these guys that make the NFL are not really finished products until they reach their 4th or 5th years in the program. Iowa's program BUILDS a lot of these guys up from raw 2 and 3 star players to NFL players over those 4-5 years. That is what they do and what they are best at. But a lot of these guys aren't ready to contribute at a high level their first 2-3 years in the program. There was an article on Kittle recently pointing this exact thing out. So while Iowa might have current guys on roster in their first or second year who ultimately become NFL players, they probably aren't ready or able to make that kind of impact right now.
Looking at that list, the question I am asking is why schools like USC, UCLA, Tennessee, and Texas haven't been a ton better based on the number of players they have in the NFL.