In this example, the missing skillset is not memorizing a book of algorithms as you seem to imply.
If performance isn't good for the use case, they should be profiling the code for root causes. Which will lead them to identifying the sort operation as a problem. At which point they can search for faster sorting algorithms which will quickly lead them to a better solution and libraries containing them (or even how to implement, if they're operating in a constrained environment where no libraries exist).
I don't want to hire software engineers who have memorized the algorithm book, that's not useful to me. I want to hire those who can apply discipline to the work, such as (in this example) be aware of performance and know how to analyze it and find solutions.