Lack of sources for BBC SO Core vs Pro version.
I find it strange and quite amusing that the demands for BBC Symphony Orchestra - Professional is much higher, and there are existing torrent/download sites/sources for said version, when its smaller (and more compact) cousin BBC SO Core seems to never got a torrent/source version whatsoever. Most of the utilities in Core are pretty much 100% usable for the majority of orchestral works, especially when it is only ~28 GB comparing to to the colossal size of over 600GB from the Professional version.
Overall, it seems that Spitfire is very adamant and protective of its golden goose in orchestral sample libraries (even though there's a myriad of alternatives that would serve the same role for less... and is also available on certain torrent sites) to continue to hunt down and shut down/DMCA sources to BBC SO torrents.