Many torrent bundles are outdated and miss the newer multi-part series.
However, once a series becomes "archived" (older than a year or two), it is removed from the free feed to make room for new content. While Carlin sells these older series on his website for a pittance (usually $1.99 or so per series, a price that has barely risen in a decade), the friction of payment gateways often pushes casual listeners toward torrents. Dan Carlin Hardcore History Torrent