Agreed: nobody is interested in everything. If someone was talking about the 19th century Slovakian art movement, I'd probably zone out.
But there are some complex systems that form the basis of civilization that just cannot be simply dismissed as "mundane", at least in my opinion. Systems that, without their presence and correct end-to-end operation, would result in absolute collapse of civilization. Systems that have been developed and perfected through the work of countless scientists, engineers, and laborers over the span of decades.
The power grid falls into this category, while the aforementioned 19th century movement does not.
Of course, I'm probably not aware of all such systems, and I'd definitely be delighted when someone points one out. Heck, I only learned about the complexity of HDTV standards throughout history on a HN thread today! It does not fall under the category I noted above, but I still found it deeply interesting.