Lack of depth on the OL and at DT is not the difference. There was plenty of depth at DT and the OL before Tangelo was brought in at DT and Wilson was brought in at Guard (he'll reportedly arrive in May).
At DT, there were still Hawkins, Darkwa, Beamon, Hansard, Mulbah, Vanover, Ellies, Brevard, Mustipher, and Izzard returning at DT (10 DT's that are not true freshmen), even after Cullpepper left and before Tengelo was brought in. What about your concern for those young players getting playing time?
And on the interior OL there were also more players competing for the 2 Guard spots (including Scruggs, Whigan, Holmes, Wormley, Achumba, Dawkins, Bruce,....) than what there now are competing for the two Safety spots (only Brisker, Sutherland, Brown, Rudolph and Jennings - just 5 Safety's).
So it's really the opposite of what you have repeated - there was more depth at DT and on the interior OL when Tangelo and Wilson were brought in from the Portal than what there still is at Safety.
You need to look at the roster before making generalizations that are not true.
It's about getting better at every position when there is a chance to do so. It always has been for Franklin, and the Portal has opened up more opportunity for Franklin to improve the roster and win games.
Obviously we don't know if Franklin is really pursuing Tykee Smith, or if he will. But if he does not it won't be due to there being more depth at Safety than there was at DT and the OL before Tangelo and Wilson were brought in to compete at DT and Guard.