Not all know the same things, but that does not mean some don’t know the same thing. Even if knowledge is not that democratic, that doesn not mean that those with the means can’t get the knowledge. The C.O.D. is rather powerful spell and is known to permanently kill demons. Why won’t powerful wizards not expend some gold to acquire such knowledge? Not only that, many people are shown to know C.O.D.. Rupert know about it, that poor wizard who cast it certainly know about it. Jehanna know about it. The magic world might not be democratic, but C.O.D. is quite popular and well known enough.
Things you told about Lenamare and magic practices might be true, however iff the knowlege of C.O.D. is readily taught to the students, then the knowledge should have been long acquired by the masters. C.O.D. seems to be one of the spells that isn’t keep secret.
Well, Exador has the necessary knowledge. He might be a cheater but he did control the C.O.D., which means he did have the knowledge. It is quite surprising that he doesn’t use his knowledge to more destructive ways or invented the bomb. He is a demon… a violent one. He is also one of the most likely to be able to figure out Lenamare’s bomb for he already has the knowledge of its mechanics.
There is also the fact that Lenamare doesn’t make a secret of the bomb. He even told Jenn how it works.
Its also not about the student but the implication. If a student can acquire the knowledge and is being given the knowledge by the teachers, then many shoud have known.
As for the heat. [-x
Yes some electrical devices can stand heat especially ones that are designed to… like your example. However many electronic devices aren’t. Household switches, electric outlets, lamps, surge protectors, etc. are not meant to operate in high temperatures. The materias they are made of will likely deteriorate. Most are made of plastic so would have melted.
Also elevators and cars contain electronic components.
Also many materials can’t stand high temperatures. And many scenes contain objects that should have not survived.
Wood would dry up, warp and crack but Ramses is playing a piano and probably the doors described in the Abyss are made of wood.
Many fabrics would degrade in prolonged exposure to heat. Silk especially is particularly sensitive. Yet Antefalken decorate his den with “silks and other soft cloths.” He is also seen flying wearing leather. Of course there are those demons that play dress up.
Jewelry, which Antefalken also decorated his den with, is also a concern . Many jewels are heat resistant but many like pearls, opals, coral, and amber would get damaged. Enamels could get ruined.
Many adhesives isn’t designed for extreme heat like wood glue and epoxy. As many modern devices depends on such adhesives, they will ultimately fail.
There is no mention of paints, but there probably be, well at least, car paint, and most paint don’t get along with heat very well. Lacquers, varnish, shellacs and other various finishes doesn’t take well to heat too.
There is also rubber tires. It would have melted long ago.
Another thing that should have been damaged by the heat are alcoholic drinks. There is a scene where Antefalken is wander in the Abyss carrying a bottle of wine, not to mention, it must have been stored in the Abyss somewhere for sometime. It would have been cooked or sour. There is also a scene where Boggy consume a truly prodigious amount of alcohol. Exposed to heat, alcohol in the beverages tend to evaporate, many also spoil. Whatever the beverage was, it would have been spoiled for being stored in the Abyss for so long.
Then there is the corrosive sulfurous air. The silver trimings should have tarnished long ago. Iron and steel would not last long either.
Well, many buidings aren’t standing and many objects aren’t in good condition but many would not have functioned there in the first place.
Really this error can’t be justified.