I don't think GOG is doing themselves a favor by failing to secure franchise / collection level bundle discounts on parity with other stores. Examples:-
- Over the past 2-3 years I've seen Bioshock: The Collection sold as a trilogy on Steam for £40 (-75% sale = £10) for B1 + B2 + B2 DLC + BI + All BI DLC + Linux version of BI. On GOG, there is no official "Collection" option but when purchased separately they add up to £64 (£18 in sale) and minus the Linux option for BI.
- Other discrepancies include mismatched bundles. Eg, Space Quest collection (1-6) on Steam = £9.99 vs GOG = 2x £7.79 (1-3 + 4-6 sold separately) = £15.58, or +55% more expensive. At time of writing it's -75% off or £2.49 Steam vs £15.58 GOG which isn't exactly the best advert for "Good Old Games".
Personally I don't mind paying a small premium for DRM-Free, but it gets harder to convince other new people to come to GOG when some franchises, old and new alike, end up +50-80% more expensive on GOG for the same content purely due to mismatched or outdated bundles / collections.