Large solid rockets have never been a very good way to build launchers that might have crews on top, especially because of the problems in getting the crew away from a failing launcher.
An experienced designer with more freedom to act might have realised that there was just too much optimism in the Ares I concept: that a shuttle SRB was simply too small as a first stage for a rocket carrying the relatively heavy Orion spacecraft.
Technically and financially, it might still make sense to give up on Ares I and simply write off the money spent on it, but politically, that's probably impossible.