Why 2013?
Normally journalists notice a big change in operating mode by a President. Mediasatans will report it with disgust when the pres has R on his shirt and with admiration when the pres is D, but under the emotions the facts come through well enough.
They've missed the giant change in Obama's mode that happened around 2013. He replaced Hillary by Kerry. He replaced Holder by Lynch. He replaced FBI director Mueller with Comey.
All three changes had major effects, though the effects weren't immediately obvious. In each case a destructive demonic chaos-generator was replaced by a semi-rational peacemaker who occasionally tells the truth.
Several ways of asking the same question:
Why did Obama wait so long? If he wanted to have a semi-rational cabinet, he could have appointed the latter people immediately. Why did he bother to make the changes at all? What made him realize the original appointees were evil?