If there is a means to provide scalar context, another to provide list context would not only solve a seeming lack in design (just a fan of symmetry that I am), but would also make for more robust module interfaces.
It's possible to return a scalar in list context (since a single scalar is zero or more scalars), which is why scalar exists.
It's not possible to return a list in scalar context (since zero or more scalars isn't a scalar), which is why list doesn't exist.
Adding list would not improve symmetry or robustness; it would just lie about what you are doing. If you want a function that returns the last scalar of a list or scalar, list is a shitty name.