aybe I'm asking the wrong questions. If these TIEs do have shields then why do TIEs not have sheilds in the EU?
I'll accept in-universe and out-of-universe answers. Preferably both.
The out of universe reason is easy. West End Games (WEG) made a dice-based game of Star Wars. Due to game mechanics, they gave the fighters no shields (that was so the Imperials could deploy loads of them, yet still give the Rebels a chance at beating them). Combine this fact with the lack of anyone outright stating they have shields in the movies, and the EU writers concluded that TIEs have no shields. When the first batch of writers weren't corrected on their mistake, the consecutive writers also jumped onto that band-wagon. This continued in all subsequent books to the point where it's a well known "fact" that TIEs have no shields.
The in-universe reason is virtualy impossible to get, as there is none. The simple fact is that the writers never took any real care in what they were doing, which resulted in a whole mass of idiotic mistakes (do I really need to bring up the 8KM long Executor idiocy again?).
Still, there's one way of looking at it that could help us rationalise it.
When we treat the fims and novels as canon, we basicaly take it as "they happened, and someone just happened to be there with a camera to record it at the time". Now, if we look at it from the point of view of a historical documentary, then it becomes a lot easier. Some things that are blatantly wrong, such as the lack of TIE shields and the min-SSD, can be put down to New Republic propaganda, designed to make their oponents look weaker than they really were. This also nicely fixes the idea that a bunch of fighters can take on cap-ships and win (I'm looking at
you Stackpole).
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