If someone is making the kind of mistakes that cause oncall issues to increase, put that person on call. It doesn't matter if they can't do anything, call them every time they cause someone else to be paged.
IME too many don't care about on call unless they are personally affected.
> If someone is making the kind of mistakes that cause oncall issues to increase
the problem is that identifying the root cause can take a lot of time, and often the "mistakes" aren't clearly sourced down to an individual.
So someone oncall just takes the hit (ala, waking up at 3am and having to do work). That someone may or may not be the original progenitor of said mistake(s).
Framed less blamefully, that's basically the central thesis of "devops". That is the notion that owning your code in production is a good idea because then you're directly incentivized to make it good. It shouldn't be a punishment, just standard practice that if you write code you're responsible for it in production.