There are plenty of people who use RAII with arenas for nested group of objects. Bloomberg for example had a strong focus on that, and they enhanced the alloca

There are plenty of people who use RAII with arenas for nested group of objects. Bloomberg for example had a strong focus on that, and they enhanced the allocator model quite significantly to be able to standardize this. This was the reason for stateful allocators, scoped allocators, uses-allocator construction and polymorphic memory resources.