A few observations, from the time I spent overseas in the '80's.
While there are such conectors made from bakelite...nothing is proof to an over-size bulb.
The wiring system used typically has plastic boxes, plastic conduit (similar to 'smurf tube'), and all connections are made on one piece of 'block.' The different sections are not normally in contact with each other.
This means that the block can bounce around all over the place, and never short to anything- unless the plastic has completely metled away- at which point the entire box and wiring is also probably toasted. Then again, that's where fuses earn their pay.
Which brings up another quirk of this system....their fuses are typically snap-in ceramic blocks, wits replacable bits of nichrome wire as the "element." One can easily replace the wire with a higher-rated one, so there is nothing to prevent over-fusing. Since the service conductors are typically uninsulated steel wire, one can easily make an "infinite" fuse.
Overfusing may also result in a melted 'choc block.' Indeed, since the box itself seems undamaged, that is likely what happened here!
A typical home is often a completely uninsulated masonry shell, with a tile floor. Central heating, as we know it, is rare. No surprise, then, that light sockets are often used for space heaters, which leads to over fusing, and so on.....
