Actually, in some respect, NASA was constrained by Congress, which required the SLS program to use existing Space Shuttle technology. The main booster of the SLS is a stretched space Shuttle external tank. The four main engines are the same model the Space Shuttle used and the two solid boosters are the same as the Space Shuttle.
Of course, that makes NASAs failure all the more glaring in some ways.
I call NASA the “dog ate my homework” agency.
They manufacture excuses in their assembly line.
Yes, I remember when NASA hired the 'best and brightest'... that time is past.