The knowledge of space-race ear rockets wasn't lost, the money to build them was no longer available or going into other projects. For the cost of shuttle NASA

The knowledge of space-race ear rockets wasn't lost, the money to build them was no longer available or going into other projects. For the cost of shuttle NASA could have recreated the J-2 and F-1. We unfortunate don't have good data on Roman private and public infrastructure spending detailed enough to really make a god case for how it changed over time.