This feels like a retcon. The real reason is most likely that Google started interviewing people this way and then that's the culture that developed in the industry. Once a culture develops, it's very hard to change.
It's also noteworthy that if you're building a search engine, these types of questions are actually pretty relevant. As a field Search demands both a breadth and depth in CS fundamentals in a way that rare in most other places.
Most Googlers joining Google today aren't gonna be tasked with the elbow grease of building a search engine from scratch, not even close.
You'll be a small cog in a large machine, engaging in theatrics justifying in length why your 10h/week of serializing/deserializing JSONS was so difficult and important to the company, while you rest and vest playing videogames at home, asking on Reddit if everyone working in FAANGs is as bored as you.
That's true, but these practices date from back when Google was a search company. My point being there existed a time when Google asking these questions made a lot of sense.
This is the correct answer. Microsoft used to ask things like "Why are manholes square" or "How many dentists are there in USA". For a while it got trendy to ask those sort of brainteasers in interviews (thankfully it didn't seem to stick).
It is very hard to change established processed - especially when the people doing the interviews have gone through the process.
They had to suffer, so why should the people after them get an easier ride?
>They had to suffer, so why should the people after them get an easier ride?
People in the middle ages and WW1 had it pretty bad, why should people after them get an easier ride?
Because humanity progresses when we make things easier for the next generations instead to clinging to the 'crabs in a bucket' mentality of perpetuating the cycle of collective suffering and suckage.
I hold a very controvertial take on the dentist question: this and similar questions select candidates who can come up with convincing lines that lack any basis in facts (i.e. bullshit). This seems to be a good foundation for a terrible engineering/company culture.