Indeed, the space shuttle was so expensive it burned up much of the rest of NASAs budget-- keeping that disastrous, failed program running is why NASA doesn't have manned spaceflight capability at the moment.
Well, from an outsider perspective, the SLS/Orion program is pure pork. Nobody holding the purse strings cares whether the thing ever flies. Heck, probably they even prefer if it never flies (always just a few years and tens of billions in the future); a failed launch is potentially politically catastrophic.