The constraints of the time shouldn't be confused with their recognition of the power of notation.
Also, based on the poor advice of this thread's subject, surely one should always write /almostall in one's DCL script for clarity and to lessen the chance of ambiguity as the command evolves? grep's -i is only ever going to mean -i.
VMS died, DCL was often ridiculed, its over-verbose style was a part of that. Its lack of power played a larger part.
VMS was written later, with a faster interface. Also, you didn't need to specify the entire long option, you only needed to type enough to disambiguate between "/all" and "/almostall" (for instance).