actually large programs that are persistent is where you really care. kernels and databases often use explicit allocators because there is so much policy wrapped up in allocation.

this goes back decades, its not just a feature of the 2020s. as a systems programmer I always want this, and the idea that allocator state should be completely hidden and implicit is shortsighted.

but yes, it is a bit onerous to pass around allocator(s). the real complaint that I have is that if 'malloc' is global and a compiler primitive, then we can do things like coalesce allocations and have compiler managed lifetimes when appropriate.

explicit allocators are an important lever, its not clear to me that we could never find a way to make them possible without the minor downsides.