That's one of the things that bugs me now.
Before Legend, Tomb Raider used to follow a strict pattern of alternation between sci-fi and magic.
Tomb Raider: sci-fi.
Tomb Raider II/II Gold: magic.
Tomb Raider III/III Gold: sci-fi.
Tomb Raider IV: magic.
Tomb Raider V: 50/50 of each.
Tomb Raider VI: well, it's hard to tell. Ancient myths based on powers derived from dark hidden science. The Periapt shards have a magical origin, but work on beings who derived their powers from atomic modifications to their genetic structure and use bionic implants (check out the sketch of Eckhardt's glove in Lara's notebook). And that must have hurt, it's attached directly to his heart.