Another point about defending SLOCs or, more importantly, the convoys that use them, is that convoys are not just a defensive tool, they are in fact also an offensive tool for locating and eliminating enemy commerce raiders.
For example space, in the understatement of all time, is just a wee bit large. A single dropper or jumpship, viewed at tens of thousands of km, will look similar to several traveling together. Additionally, having them all running around seperately, just increases the number of targets and makes creating an escort force that is effective almsot impossible. Also, if your stupid enough to scatter your merchants you are probably putting together the biggest misnomer of naval warfare - hunter killer groups. They dont work. The sail around whilst the commerce raiders avoide them and kill isolated merchies.
However, mass all you transports together with a massed escort. Now either the raiders show up and get crushed, or see the escort and stay the hell away. This is why you form convoys and escort them, you gain two fold benifit of protecting the merchants and causing attrition of enemy raiders.