Everything else is haggling over the specific details. If we decide that one of those employer obligations is to provide guaranteed runaway for employees in the case of termination then that’s that. If we decide that one of the employee’s obligations is providing 3 months of notice then that’s also that. But the two things aren’t at all related except in your mind.
Right now today with no change in policy whatsoever you have to make the choice as to weather you are willing and able meet your obligations as an employer before taking on employees and you have as much say and the same votes as everyone else to decide what those obligations are.
Fairness informs but does not ultimately decide the employer employee relationship. The only thing we get for sure if the system works is that over time it tends toward what is considered fair by the current working citizens.
Welcome to "government is the means by which a group of people make collective decisions about the way we want our city/state/country to work." When striving for liberty, the thing we actually want, anarchy is just as much a preference as order.