That isn't true at all.
iDL -
4* - Bethel, Silvera
3* - Martin, Ford, Miller
EDGE -
4* - Jackson, Garvin
3* - Jackson, Patchan, Rousseau, Joyner
This is what was left from the 14-18 classes...four 4* players, seven 3* players.
Go ahead and compare that to any of the really talented D-Lines (Alabama, OSU, Clemson, among others) in the country and quickly realize that the numbers and blue chip ratio isn't even in the same discussion.
Also, quickly realize that last year, starters...Thomas, McIntosh, Norton, and fan favorite/heavy rotation player Trent Harris went R3, R5, R7, and UDFA respectively.
Due to the lack of numbers in recruiting...we've had to get transfers like Gerald Willis (former high 4*, now a senior, with a career 5.5 TFL 1.5 Sacks) and Tito Odenigbo (former 3*, rotation iDL for Illinois with a career 7.5 TFL).
If you think that unit is "one of the best in the nation" you need to go check out some other DL and take a look at what they've got on their roster. Its just not.