Note: this is narrowed down to IT industry to make it answerable.
I have asked this question which initially gathered several downvotes and a couple of close votes.
That was clearly my fault because I failed to properly describe the context and a few users thought that I am trying to ruin a colleague's professional life. Also, I think the IT market where I work is very different from the one assumed by the most active users around.
I am interested in what is the assumed context when the OP fails to properly describe it. This is vague, so I will describe the work market where I work to pinpoint what I am interested it:
IT work market - it is an "employees market". Virtually all employers are complaining about not being to find talented programmers, project managers etc. IT workers are among the best payed workers in the country. It is not unusual for experienced workers to be frequently called (LinkedIn etc.) for interviews.
payment - almost always on time and everything is official. This is normal in high developed countries, but in a country with high perceived corruption, there are many grey areas when it comes to employment and payment.
firing - (law) you cannot just fire a person which is a full-time employee. You must issue an official warning first and design a plan to try to find a better place for that person in your organization. Even if you manage to fire, the employees still 20 working days which can be reduced to allow them to find another job.
overtime - (law) normally a worker is not allowed to work more than 48h / week. Any full day overtime must be payed + free day. In practice, this is more flexible.
Question: What is the assumed work market context for IT related questions when it is not fully specified?
Usually if the information would significantly change answers, we try not make assumptions at all. Instead we add comments asking for clarification, and sometimes will close a question as unclear if the missing details are critical enough. We most often ask for a location, because labor laws can have a significant impact on how to interpret a situation.
That being said, the four categories you mention do have some general assumptions that are usually made.
Job Market - It's usually assumed that there are jobs available on the market, and that anyone should have the ability to leave their job. We never assume that there are enough jobs that you could quit and expect to find one next week.
Payment - It's assumed that payments are on time and on the books.
Firing - This is one that will depend greatly on location, but usually we assume that anyone can be fired for any reason, since that is the worst case scenario. If we are given more location information, then assumptions can be adjusted.
Overtime - I don't think there's any general assumptions here, since this will depend completely on local laws and employment contracts. Many salaried positions have no overtime at all. If this is relevant to the question, we will ask about it.
Again, these are general assumptions when the info is not super relevant to the question. If you are asking a question about your boss threatening to fire you, we will ask you more specific information to determine what applies to your situation.
What is the assumed work market context for IT related questions when it is not fully specified?
Ideally, there is not an assumed anything if it may change the answer to the question. If a question depends on a factor that is not clear, there are several options for potential answerers. These are the steps I take, generally in this order of most preferable to least preferable:
Ask for clarification. Often, the OP will answer quickly. If the answer is in a comment, edit it into the question. This preserves their answer, since comments are transient and may be deleted without any trace.
If the OP does not clarify, and the question is generally answerable otherwise, write an answer but make your assumptions clear. If you must assume something, say so in your answer. Besides making it clear to the OP if/when they read your answer, you are making it clear to future readers. Part of the value of SE is building up a volume of well-answered questions. Even if we all agree - here, today - on what we should assume for work market context, things may be very different in a year or two. If possible, these answers should also include information on what would change if the assumption is not true. For example, if the answer is basically don't do X because of Y in some assumed jurisdiction, but being in a different jurisdiction would mean Y is fine, the answer should say so.
Finally, if the OP does not respond with clarification, and the question is unclear to the degree that it is not answerable - as a last resort, vote to close as unclear. Best case, the question going on hold gets the OP's attention and they finally come back and clarify. Worst case, the question getting closed prevents people from making unfounded answers in an attempt to be helpful.
Based on those three approaches, I don't think there's really any value in trying to come to agreement or understanding the basic assumptions, because if an assumption could reasonably change an answer, we should either not answer (without clarification first) or we should clearly describe the assumption in our answer and - if possible - state how that assumption being different would change the answer.
Other assumptions that I noticed, but that are not in your list:
Workers have well defined roles in their contracts and stick to them. They are not overzealous, they don't step on other worker's ground.
Companies are well staffed. Workers have managers, bosses, HR... It's often the case in medium or big companies.
Basic Human rights are respected. Workers talk each other with respect, they don't yell at each other, humiliate, insult, judge... (I've seen some questions where in some places it seemed OK, when in most countries it's not).
When it's not the case, user should specify it, because otherwise, the answer will often be: "It's not your job to deal with it", or "Talk to your manager/HR".
I think if there is any assumed work market context, it is that of the reader. And hence the problem. If the question does not specify enough context, readers and answerers are likely to consciously or subconsciously attribute their own context to that of the question. Clarification from the question poster is the best way to constrain the context.