Why so many languages have allocators now

3-Second Blueprint (English)

1. Stack allocation bumps a single offset pointer in contiguous memory for speed and cache locality under LIFO call order.
2. Zig and Odin pass explicit allocator interfaces, while Rust parameterizes heap collections like Vec and Box generically.
3. Arena and power-of-two buddy allocators reduce fragmentation and overhead, inspiring arena APIs even in Go and Java.