*edit: contract work is very common and definitionally does not define 'time on the job', and instead lays out specific metrics of performance related to production. Salaried work is definitely far more common, but to say that's unusual or impossible is just wrong.

I think this helps elucidate the real issue here, which is the distinction between selling labor and selling your time. One of those is obviously more reasonable and the other shares a conceptual relationship with other types of indentured labor.

It used to be that the distinction didn't matter since you had to be in a particular place to do a particular work anyway, selling your labor and selling your time looked basically the same and your employer could control and manage how you spent that time. But with remote work, the employer no longer has control over managing your time because they have no (reasonable) way to monitor your production; an employer utilizing monitoring software would (rightly) be seen as an abuse and invasion of privacy. So even though the contract hasn't changed, people are more aware of how dehumanizing it is not to have sold their labor but control over a certain number of hours of their life.

I obviously have bias here, but I think defining labor by its measure of time is alienating and inhumane.

it definitely happens.

My point is more that salaried employees, by definition, are not required to put in a certain amount of hours. That would make them hourly employees. All salaried employees are required to do is to complete their work by a deadline. What that work is and what the deadline is are usually not defined specifically in their contract, because as you said, both those things constantly change, so it would be impossible to reflect that in some binding agreement.

It's less about contractual and legalities and more about the feel of the workplace. A lot of places, especially remote jobs, are more laid-back and open-minded than traditional 9-to-5 ass-in-seats old fashioned office jobs.