I know what you mean
But you can't really just say something like SortedCollection should implement #detect: as binary search. Its a general purpose method and the aspect you are searching on may not have anything at all to do with the sort ordering.
I've found some find: methods that return the index. But again, because of the nature of the evaluation block, they do a linear search. I've spent a few minutes looking for a #binarySearch: or similar and haven't found one. Of course, you can add one without much effort.
Smalltalk culture is pretty much about efficiency of coding - with efficiency of implementation being seldom considered until its crucial.
Actually, there appear to be 2 cults - one dedicated to elegant simplicity of coding - which is nearly everybody - and the other dedicated to really clever (and transparent) optimizations - like the people working on croquet that are transparently offloading graphics operations to hardware as much as possible - or the people who work on the VMs.
"I believe that many of the systems we build today in Java would be better built in Smalltalk and Gemstone."
-- Martin Fowler, JAOO 2003