And honestly the difference between science and engineering in systems is overrated. The real difference is "systems that work, or everyone knows how to run" vs "systems that are a bit of black magic".

While on paper it is true that HPC has had collectives and dragonflies and RDMA for ages, a whole host of issues make tuning these things hard and tedious. Such work also informs the design of future "smart networks" by keeping everyone updated with common problems and workarounds that folks employ.