The lack of an independant regulator is a significant conclusion nut not one without its irony. This was considered a key factor after Challenger and these institutions were put in place. The CAIB findings suggest that the regulator did not remain independant and it was NASA's political and commercial proponents who made key go/no go decisions.
More than everything else it was the "we usually lose foam, it often hits the orbiter and damages the tiles but we have never lost a shuttle from it before so we can ignore it" attitude that caused this crash. In fact that is not quite true, they had been working on solutions to the problem and had intended to get the problem resolved within the next couple of flights. This therefore depicts NASA more as a knave than a fool; they had appreciated the danger and had ordered it to be fixed, but did not ground the craft until it had been. This was a soluble problem and you can bet your bottom dollar that no foam leaves the booster on STS-114.
It is hard to imagine an independant regulator allowing the flights to continue under those circumstances.