A senior editor at a top-tier medical journal told me >5 years ago that they have hired staff dedicated to scrutinizing papers from two countries that have poor reputations when it comes to submissions. It's not just prestige and the career boost; in some countries there are monetary incentives associated with publishing in the top journals.
> in some countries there are monetary incentives associated with publishing in the top journals. Meaning the authors get paid the more they publish? How? Per paper or career advancements-->> higher salary?
That has been a good incentive to date (I insist, this is maths and there are very few possibilities for cheating in my field, but of course there are instances), as I see it, because this way you incentivate academic professors to really do research (otherwise one can have a truly leisurely life in Spanish public universities once one gets tenure, without any repercussions).