Maybe I didn't express myself properly (English is not my native language), but the point wasn't that everyone should use Memory Arena™ instead of Smart Pointers™ or Borrow Checker™. I am not trying to sell a conference here :)

The point was, to put it in Mike Acton's words, "when there is one, there are many". Usually, things are grouped, perhaps semantically, and it make sense to think of them as a group rather than breaks them in pieces. Arenas are one rather simple grouping mechanism, but they are not the only one. Of course, explaining complex grouping will require explaining the associated problem-solution pair, which is obviously out of scope of a forum reply.

All I would say is, if one steps out of one-at-a-time thinking, and statically plans the dynamically happening data transformation, and therefore exploit patterns and relationships inherent in that data flow, programming in low level languages becomes much easier.

But you need to know the problem (really really know it), and you need to know the solution. Temet Nosce.