I think the history and "if it ain't broke don't fix it" rationale has been covered.

As for compatibility, any aftermarket 9 speed crank with Octalink (Shimano) or ISIS crank interfaces will work with Campy 9 speed derailleurs. Thus far, only FSA has offered the 10 speed option in the aftermarket and they offer crank options that'll work on ISO Std. square tapers (Campy), JIS Std. square tapers, Shimano/Octalink or ISIS.

You may want to take note that not all square tapers are the same. Campy continues to use the ISO square taper standard which uses shorter and slightly steeper flats than the JIS standard that Shimano and other Asian component manufactures developed. As you would expect, Barnett's and Sheldon's web sites go in the details of the differences. All you need to be aware of is that there is a difference.

Race Face manufactures its square taper BB's to the ISO standard, Phil Wood offers your choice of ISO or JIS, Campy does ISO; however, Shimano and most of the other spindles coming out of Asia are machined to the JIS standard -- regardless of what name brand they are sold under.