Tee Emm, I suspect it's all to do with the difficulty of manually setting a lower than full power throttle setting. I don't fly the 737, but if as you say there are no 2000ft/min N1 figures anywhere, it's easier to just set full GA power and concentrate on flying the GA itself.
On two engines, it is obviously desirable to climb at reduced power and this is therefore designed into the automatics. Given that automatics are the preferred method of operation these days, Boeing assumes that they will be used on a GA and so have built in the 2000ft/min first press.
But FSF has now built-in a pay-wall to prevent easy access to the old ALAR Briefing Notes
Good one, FSF.
Icelandair Boeing 757-200 at Oslo Airport Gardermoen Norway 22 January 2002
Wow!