The manufacturer designs a checklist system with the understandable assumption that competent trained crews will use it.
Sadly the main aims with those manufacturer designed checklists from boeing has been shifted to quite different targets in the last 10 to 15 years. Main target is now to produce a fleet commonality where no such thing exists (at least not if compared to airbus), the second main thing is that they have to be checked or written by lawyers to keep free of possible court cases.
For example boeing has already an EASA approval (and i guess FAA as well) for a reduced type rating course for the 787 if coming from a 737, 757 or 767. The next step they work currently on is a CCQ to allow mixed fleet flying between those original types and 787. My company plans to do that and works with boeing to develop those standards, same as we had already EASA approval to fly 737 and 757 as well as 737 and 767 in a mixed fleet. Mixed fleet in this case means that one enjoys the same rules as for example A320/A330 mixed fleet flying, no dual sim-checks, switching between types as easily as between variants and so on.
Apparently (please correct me if i'm wrong) other boeing aircraft have different pressurization setups and it is quite enough to check the bleed valves, which lead to this checklist design.