The original set up for "caged" was toe clips and toe straps, with cycling shoes having leather soles and metal shoe plates nailed on them. This set up was very difficult to get right as there was no "float". If you road them with the straps tight, it stopped the blood circulation in your feet. And in the event of crashing, your feet were likely to remain fixed and you could further injure yourself from getting caught up in the bike as you fell to the ground.caged rider to be at any tangible disadvantage to one running clipless.
Clipless solves all these issues. No blood circulation issues and generally separate when falling. Cleats are bolted, rather than being nailed and have float to make easier when setting up.
Cages with trainer shoes solve some if the original issues, but don't deliver the absolute secure footings that clipless now provide. But not a bad compromise.