Immediately after takeoff is no time to be distracting PF with non-essential challenge-response. So who cares if the gear or flaps are not up? It will fly like a dog,
Keep in mind that when a reputable manufacturer like Boeing or Airbus design a checklist, they just don't fling a few words together and say try that. There is careful research into its design and applicability to the environment in which the aircraft will likely be used. Then it is thoroughly checked by qualified test pilots and no doubt by the aviation human factors people. Finally it's a good bet the legal people go through it to minimise the chances of future litigation if some dumb pilot from a dumb operator changes the manufacturer's checklist to suit the chief pilots ego.
To say as you do, that "who cares if the gear and flaps are not up" by the time you reach 10,000 ft smacks of an amateur pilot response and really there is little point in continuing the discussion.
The Boeing 737 FCOM gives the hint on the importance of exactly when to read the after take off checklist when it states: "After flap retraction is complete do the AFTER TAKE-OFF CHECKLIST." It doesn't say wait until 10,000 ft. Another pertinent paragraph this time from the FCTM states "After flaps and slats retraction is complete, select VNAV or set desired climb speed in the MCP speed window. Before selecting VNAV, flaps should be retracted because VNAV does not provide overspeed protection for the leading edge devices."
In any case it is logical to check the pressurisation early in the climb sequence (it takes less than a second to look at the cabin pressurisation needles) as per manufacturer's advice which is after the flaps are up, so that any unusual pressurisation indications possibly requiring ATC notification, can be dealt with before reaching 10,000 ft when the cabin altitude warning horn may sound requiring a flurry of QRH activity. The crew will look a bit bloody silly if no one had twigged the aircraft wasn't pressurising before being notified by an aural warning.