I feel inclined to contribute to the question, but in part so as to answer something else. Sorry if this out of line.
A question of importance to people with a permanent academic job, and hence of importance to people seeking one, is How does one learn to determine which of their results are significant enough to submit to a top journal, without losing their interest in mathematics?
As a grad student, I was convinced that landing a permanent job was the end goal of the absurd game of mathematics journals (which I found fun, at some point, oddly). It turned out I got caught in a never-ending sequence of further competitions (for advancement, for leaves, for bonuses, for recognition, etc.) which put the publication process ahead of the mathematics, to the point I was wondering where a result could be published before finding a proof. Despite getting a full professorship quite early, I often felt inadequate and lesser than owed to my rank and than my peers. Of course, everyone recognizes impostor syndrome in this, but even recognizing it does not suffice to cure it.
While I might very well go back to academia, it went to the point I took a leave of absence to train as an actuary. This helps me feel things differently but testifies to a heavy toll this publication shenanigans can have.
So, my answer is: whatever determines the acceptance in a top journal⁽¹⁾, the maths and your interest in it should go first. Try not to let the competition needed to get the job you seek print itself on you, do things because they interest you and not because they might land you a job---otherwise that very job could turn depressing instead of liberating. You are not your publication list, even when we, as a community, do an awful lot of efforts to let you believe that.
This matches my advice about whether one should take the next postdoc: do it if it's fun to you, not for the sole sake of landing a permanent job which may never come. So, do not hesitate to send to a top journal a result you are very proud of, but never take them too seriously; they do not deserve it, and even if they were completely objective and transparent, the whole thing is still built in a way that lets 99% of people feel subpar.
All this is easier said than done. While I do not always agree with Doron Zeilberger, I think reading his opinions can be a good way to detach oneself, emotionally at least, from the cult around these top journals. Talking to a therapist can help a lot more people than those who actually admit seeing one.
⁽¹⁾ As far as I understand, it all boils down to whether editors will get excited by the paper (possibly through the excitement of the quick opinions they ask if they are not bored right away). There are easy cases for acceptance (solving a well-known decades-old conjecture, although there are infamous counter-examples) and for rejection (your typical good-but-not-great paper, the kind which you can produce regularly---only applies to people who do not solve well-known conjectures regularly), but other than that, the composition of the (usually quite small) board determines what has more chance to get through.
Different fields have different publication habits and structure, e.g., in dynamical systems I have the feeling that the room available in top journals has increased, slightly decreasing the relative selectivity of top field-specific journals.
This answer is still very vague, but this is unavoidable. The whole publication process is very informal, with very little explicit policy, and very little accountability, but plays an incredibly central role in the organization of our community. I think this is at the core of the problem you raise, even before talking about cliques and mafias (which certainly do exist, at least to some extent). Even with the best will in the world, if you make a choice that obscure matter that strongly, you are doing something wrong. We are definitely doing something wrong.