It's a little more nuanced than that. Phobos is moving towards a more pipeline style, of which http://dlang.org/phobos/std_algorithm.html is a standout example.

Algorithms, by and large, do not need to dynamically allocate memory. By converting more of Phobos to being algorithms, they become agnostic to whatever allocation method is used. Allocation strategy becomes a high level decision, rather than a low level one.