This opinion might be a bit controversial, so correct me if I am wrong.
Going by the Think Fast Think Slow, most of the people who were great at what they did, could be categorized overall, in terms of how they put in their effort, where they put in, and when they started from. (Apart from luck)
I think of this in terms of traits. Big tech companies, they would want to avoid any form of engineering silos, giving so much power to a single/single set of engineers, that would halt their business. Which is why they have this process.
They want a whole lot of easily replaceable engineers, who (might work on different projects), but overall have the same kind of mentality. This way they know, if the candidates have done what they need to do, and talked about things a certain way, they on a fundamental level would be the same.
So even if the person leaves, the style of work for the next incoming engineer wouldn't change, and everyone can go along with minimum friction.
Also, thinking a bit more, /^[FAANG]*/ companies would obviously try to cross-hire. Same as BIG4, same as /TCS,CTS,Infosys/ and likes.
A good chunk of people who work in MNC's stay in MNC's. Infact sometimes the projects are transferred from one MNC to the other, and then the manager or TL or whatever leading the project is hired first, and then he/she brings his/her team from the previous org.
Although end of the day, there will be a few hits and misses, but given the plethora of people working there, on a large scale of things, it doesn't really matter. I mean in a group of 20 people, 2 leaves. Its barely anything to make a dent.
> Let us know if you’ve seen the problem previously.
It was one thing to practice this for hours, and now I have to tell them, yeah I saw this problem, so given me something that I never solved, and have a 50-50 chance of win.
So working at Meta would be like, oh we need an Auth layer, but we have already seen an Auth layer being used, So lets scrape that, and build a new one, but then we are not going to look the spec or the problems from before, because we want to do the same things again.