On one hand, this is a classic dictatorship move. Senegal just did the same just after postponing elections. On the other hand, Pakistan really did have terrorist attacks just before the election, targeted at the election. So taking heavy handed steps to protect the election integrity can be explained.
IN Pakistan army decides and is the real ruler. Elections are only a face to appear as a democratic sate. In fact Pakistan elite (including army higher ranks) just is there to milk the country and build estates outside (West/UAE/etc).
If you want to see how fast things show their true colors stop paying "your" soldiers. When it happens due to breakdown of government-nation relationship coup or military pacification of civilians is imminent.