Peter, your first inference is correct, but I really don't think it was being presumptuous, mezzo-presumptuous, or even pochissimo presumptuous to suggest that "an old form ' may have died out "because of computer limitations" OR that it might simply be a matter of house style. I was simply posing a couple of possible explanations for an interesting phenomenon.
However, it wouldn't be the first time that computer limitations have affected an engraving standard. Finale could not produce an automatically centered multi-measure rest for double-staffed instruments until very recently, and only now with a Lua plug-in (thanks to Charles Lawrence) that requires re-centering when a staff is moved. http://forum.makemusic.com/default.aspx?f=6&m=462676
During the same period, we accepted as a standard something that was much less standard until recently: numbers on both staves of a double-staffed multi-measure rest.
Could there be a connection?
If there is a connection, a standard preferred by excellent publishers for well over a century has been discarded because Finale cannot automatically center expressions between the staves. (It is this limitation that causes someone writing for double-staffed instruments to constantly recenter dynamics between the staves during page layout.)
I don't think that it is being presumptuous to say that I prefer this older system for double-staffed MM rests. To me, it is more economical and more visually pleasing.
I also prefer the older style for measured repeated note abbreviation. For me, the Brahms 4th example with contemporary slashes is ugly. Beams and sub-beams of simple repeated patterns even when abbreviated should follow note direction, not clash with it.
However, the unmeasured tremolo may be a different animal because of all the slashes involved. In this case, the modern system might be the better choice. It is unfortunate that the abbreviated measured repeated note and the unmeasured tremolo find themselves in the same soup. They are different phenomena and probably deserve different treatment.
The actual reason for the change in both measured repetition and tremolo style has yet to be determined. Knut's information about Kurt Stone's handling of this in his book from the 1980s and your information regarding Notaset from the same period is intriguing.
As a power user of Notaset, would you say that it would have been practical to produce the older style with Notaset?
Mac mini (OS 10.8.5) with dual monitors, Kurzweil Mark 5 with M-Audio Midisport 2 x 2,
Finale 2014d with GPO 4, JW Plug-ins, SmartScore X Pro, Adobe InDesign CS4,
Inkscape .48.5 and .91, FontForge 20150526