Those compensation requirements would basically make it financially impossible to have someone on-call or they’d just have to hire people for those hours and say they are normal working hours

These are not the only options. Here are some others:

1. Ensuring the on-call load is shared more evenly so that everyone is woken up under the painful limit
2. Fixing the broken shit that keeps waking people up, which they keep ignoring because “it’s low priority”
3. Hiring people for a night shift, appropriately compensated for their diminished health and other life impacts. The union can ensure such positions aren’t paid the same as normal work hours while not being prohibitively expensive. Night shifts are a standard thing in some occupations

Something’s telling me most orgs where 2 is an option would go with that. Related to that - increases in labor compensation is what forces companies to spend money on capital investment that increases productivity - read new equipment, automation, fixing broken shit, etc. If there are cheap enough slaves to wake up during the night, doing this investment is “low priority” (more expensive) and isn’t done.