This is an interesting start. I would say that the next (and possibly easier) step is compiling the reference books associated with these subjects, the original sources and their best versions (such as comparing translations and editions). I think starting to add these in other companion lists could also prevent people from suggesting original sources and reference books in lieu of textbooks. One good thing about a list of textbooks is that it shows just where market opportunities exists for potential authors, and also where the bar is already set high. I have observed perfectly authoritative books being "replaced" for no good reason. This may be encouraged by publishing companies due to the way copyright works. However, changing textbooks every few decades does not help the process of imparting understanding. Something like this list might help prevent that.