Simply asking about average salaries around multiple countries is off topic here for multiple reasons. One is that they are very much "shopping-style" questions, which is off-topic on most SE site, and on the other hand as stated they are not really expat related.
I went through some salary related questions we already have, and I have the following assumptions:
- Asking if a specific salary is enough or not is borderline okay. It can be argued that someone who is new in a country will not know what costs they could expect as net salaries and cost-of-living can vary widely between countries, so it's related to expats. It can also be helpful to other visitors so it's not too specific.
- Asking about comparisons between countries could also be borderline okay. E.g. questions like "I am currently earning $X, but I will earn £Y afterwards, is it going to be better or not". These questions are similar to above.
- Questions related to taxes on salaries, especially if there are different tax regimes for expats are okay - but we also accept questions asking about how taxation works in a country.
- Questions about taxations across multiple countries, e.g. where you have to pay taxes is still relevant to expats and therefore is on topic.
Also I usually give a small leeway before closing questions as off-topic as sometimes there are circumstances that become clear during an answer. However the question mentioned doesn't generally fit into SE's format as well so there's no point in having it around.