Interesting. Part way through this switches to a narrower focus but the general concept applies to obsolete philosophy or discarded theories or anything else that has essentially been "overruled" by later works. One could even make the case that Newtonian physics is an obsolete ideology.

Philosophy in particular has great deal of old stuff that sticks around because it was first, even though large parts of it are now irrelevant. While it makes an interesting historical study, it now borders on bad philosophy. I have no specific examples to share, however, this is just an impression.