I would like to spend my humble opinion on this.
The real problem of RC is one: it is time-consuming.
Explaining a question why is wrong or right, especially related to a LONG reading and difficult passage (see the latest I am posting from GRE - they are even tougher than those on the real GMAT) really need an above-average dedication to explain.
Moreover, more often than not (but this is not clear evidence) the students do not ask for the most difficult ones or when is not clear a particular sentence or correlation among the paragraphs: no, sometimes they ask the entire bill. All the questions explained.
Notice that on youtube, the tutors who go through this process (explain a long passage - which is more usual - with 5/6 answer choices) spend 40 minutes more on a tutoring video.
Personally speaking, I am usually on the RC forum and I help as much as I can. And I think of being an expert. At least an advanced student
SC and CR are shots/bullets. RCs, in particular, those from these tests, are a form of art.
Look at this one provided by me (answer):
https://gmatclub.com/forum/flatfish-suc ... l#p2304032I had to read two times the passage, jot down a clear and useful explanation for the students: 10/15 minutes overall
Maybe
GMATNinja is faster than me.......but I do not think so
Regards