I mentioned three ROOKIES, not three DRAFTEES. And I fail to see how they signing an undrafted player is any different from having picked them in the 2nd round, for the purpose of the argument being made.
Also, it's a fluke to have three rookies succeed on the same team, as much as it is to select any group of three rookies drafted at their same positions (one undrafted) and have them achieve similar success. So that would be the baseline for you to compare, that having three rookies simultaneously hurts their chances relative to their development otherwise, not that it is unlikely for three rookies to succeed (together or by themselves).
How exactly? Jalen Green's game developed fine, Sengun showed more promise than any of our rookies, and I fail to see exactly what Garuba's play supports your argument, since you'd have to prove it's because he was drafted alongside 2 more rookies.