https://blog.cognifit.com/motor-memory/
https://www.vanderbilt.edu/olli/class-materials/Neuroscience...
Where are you getting this concept that humans never forget skills? That's completely false.
So from this rule, if you just learned the rules for chess you would forget them. But if you started trying to win chess games and viewed the rules as building blocks for strategies, then you will remember the rules for chess. Then you start to compose strategies etc.
I never said humans never forget skills, I said humans never forget skills they master. Most people never master much at all, maybe 90-99% of software engineers would be in the never master bucket. Which is why I get downvoted, most people never get good and get angry when you tell them that they can work to improve.
In terms of working to improve, given the excellent filtering capabilities of algorithmic interviews, surely if people were taught right and knew how to master it not to mention what they should master in the field, then it would not be so difficult to improve (though this would render the filter ineffective)? Because then more engineers would have known from day one what they should focus on (not that they don't at present, because these interviews are now broadly known to the public), and thus having mastered the material, be passing the interviews easily.
Interviews are not an exam, they're a filter.
No one is testing your ability to do cutting edge original CS research in these interviews. It's just basic fundamentals
Also, recall would only be an issue if they didn't truly master the material. Do you need to recall how to ride a bike after you've learned to do it?