1) Salary can include tasks like this.

2) You said they want to. They dont. If you offer same pay for a job with and without it, exactly nobody would choose the job with extra on call duties.

The obvious part you are missing is that people do it because they are paid to do it, and they like money.

> Salary can include tasks like this

So lets say that it just magically happens that when YOU are on call, stuff breaks all the time but when its your coworkers it doesn’t. You are all paid the same, does it seem fair to you now?

Unless it’s written in paper where a salaried worker will be getting X extra per hour you are just working for free. The definition of a salaried worker in the US is having 40hrs of total work time averaged throughout a year.