They had trouble with simultaneous releases when they put out 4e, there were some troublesome proofreading/quality issues. So with 5e, they put out the pieces one at a time, allowing each title to have its own turn to be the urgent, top priority.
I started running 5e before the release of the Monster Manual 5e, using the smattering of monsters in the back of the PH. It was limiting, but fun in its way.
They had trouble with simultaneous releases when they put out 4e, there were some troublesome proofreading/quality issues. So with 5e, they put out the pieces one at a time, allowing each title to have its own turn to be the urgent, top priority.
I started running 5e before the release of the Monster Manual 5e, using the smattering of monsters in the back of the PH. It was limiting, but fun in its way.