I think the inverse proportionality is probably wrong since entry-level cameras generally never get mounted on anything. Arca Swiss mounting on my mom's camera

I think the inverse proportionality is probably wrong since entry-level cameras generally never get mounted on anything. Arca Swiss mounting on my mom's camera wouldn't be particularly useful. I don't think a multiple-thousand dollar camera body is a good target for invasive modifications unless it's already out of warranty, regardless of whether the change is being made by someone with the appropriate skills. I also doubt that the result of such a modification would be very good anyway. Without being part of the initial design (e.g. a captive nut embedded in the base), the best aftermarket modification would likely be based on either threads tapped directly into the body or a nut essentially glued in place.