You mentioned students applying for IB positions at target colleges. Students who are admitted to target colleges, choose to matriculate to target colleges, choose to apply to IB, and choose to be involved in IB clubs is a very different group that general high school students who choose to apply to highly selective colleges. There are many contributing factors to why the former group may have better success in IB admission than most. Interview preparation and school support are part of it, but there are other, more influential factors in my opinion.
There are many types of jobs that have different selection systems. CS and finance were mentioned. CS and finance positions often have very different selection systems that emphasize different types of criteria. Both typically have noteworthy holistic elements.
For example, in the paper at https://www.thinedgeconsulting.com/assets/pdfs/Ivies%20extracurriculars%20and%20exclusion%20Elite%20employers’%20use%20of%20educational%20credentials.pdf , the author works with 120 persons involved in “elite” IB, consulting, and law hiring. They describe their hiring process and evaluate mock candidates. Roughly the same portion of these 120 employers said they used ECs to screen candidate’s resumes as they did school prestige. A larger portion said they used ECs to screen resumes than GPA. Some employers are quoted as making comments like below, which sounds quite holistic and may be difficult for some students to learn via practice interviews.
“We look for someone who’s got a personality, has
something to bring to the table. You know, for lack
of a better term, someone you can shoot the ■■■■
with… Typically…they were in sports, they were
involved in different activities on campus. The more
well-rounded individual versus the candidate who has
the 4.0, who’s got all the honors and all the different
Econ classes.”
CS employers often emphasize technical interviews that involve solving problems using a CS skillset. However, they also often evaluate applicants on how well they fit with the team, culture, … Many tech employers have an interview primarily dedicated to fit, rather than just focus on technical skill/ability. It’s also evaluated when you have lunch with other employees, go to interview day events, etc. When I was interviewing for engineering jobs as a new grad, larger companies sometimes had events like bowling to evaluate this type of getting along with group/personality/fit.
I don’t think one can say employers are more/less holistic than colleges. Instead you need more detail about which employers and which colleges for which applicants. There is a lot of variation.