How do some researchers consistently get published in venues with low acceptance rates?
Since people rarely document papers NOT published, a 100% success rate for papers in a CV is kind of guaranteed.

It does often seem like some PIs have the 'magic touch' when it comes to publishing, and here are some factors that may contribute to this success:


they work on a very hot topic
they are very established


[a] unfortunately publishing begets further publishing as ones name becomes associated with a high quality record
[b] they are possibly personally acquainted with some of the reviewers, which could help grease the wheels

they are at a top institution (yes, this probably helps)
they are working on several projects in tandem and so submit more papers in general
they may be a pro at working the review process: invalidating certain dissenters by request or by inviting comments on a  manuscript prior to publication (disqualifying them), or through fierce contest when papers are rejected. 


The publication process is far from a perfect or even acceptable, and many factors contribute. Those that know how to exploit these factors will be more successful, deserving or not.