It's been 15 months, that's enough time to see results from poor decisions. Sure, he would need to be unusually competent to prevent such issues, but arguably that's a reasonable expectation for a president.
(I say this as a government contractor.) As to root cause for Gov IT issues, the real issue seems to be the government outsourcing so much. It makes many people rich, but outsourcing ends up being both extremely expensive and error prone. This is not purely an issue with the government most private companies face issues when outsourcing IT as it's difficult to get right.