In standard-land, not so long ago. The process is slow. As for the Lakos allocator model, two issues come up: (1) You get an allocator pointer in everything.

In standard-land, not so long ago. The process is slow. As for the Lakos allocator model, two issues come up: (1) You get an allocator pointer in everything. (2) Each allocator still doesn't get to be simple: if the container passes the allocator down to its elements, the allocator has to worry about very differently-sized allocations. E.g. rb-tree nodes and the contained types.