With the discussion of getting Rust into the Linux kernel, I think there's more interest in graceful recovery from OOM errors. The new Allocator API will (maybe?) help this.
The Allocator API is about the ability to mix allocators and provide "precise" (per-object) allocation strategies. That's orthogonal to fallible allocation, which is mostly about adding fallible versions of possibly-allocating APIs, and being able to statically remove access to the non-failing one (and being able to implicitly reject any dependency relying on those APIs) (and / or providing alternate implementations which expose a fallible API which is what fallible_collections does, but the stdlib seems to have gone with adding fallible APIs and probably adding a compiler feature / flag to be able to disable the non-failig ones)