Puritan value judgments don’t help and any analysis based on concepts of digital sobriety or arbitrary definitions of waste should be rejected.
"This is completely different from the physical world where there are real limits and space is truly “used up”."
I am afraid you are mislead here. Digital world is equivalent to energy expenditure in term of minerals mining & refining, HW manufacture, transport, electricity for running the infrastructure and so on. Except for the transport which is powered by oil, the rest is mostly coal or natural gaz.
Digital sobriety is about reflecting about our real needs and cutting out practices we recognize as unnecessary as to decrease the energy "wasted" (since we qualify them as unnecessary). If you divide by 2 the amount of data transfer from a data warehouse, I can assure you that the owners will halve by two the amount of disks, switches and so on, which is exactly the point of sobriety (saving energy, i.e. CO2 emissions).
Even if we lived in a world where electricity is abundant (by means of nuclear fusion for instance), we would still need to quit our unrestrained behavior because the minerals needed to produce HW is also finite and some studies show that, for some of them such as copper, the production peak is to be expected in 2024...
This process of sobriety can be either voluntary, or, enforced if people are not understanding the need for energy saving. The former would be much preferable, but it requires education, which is much more difficult to achieve than passing a bill.