In this regard, A lot of interviews are designed to test soft skills.

I know many recruitment teams aim for soft skills first because they don't want to bother their technical staff if a candidate is not a good match.

Many algorithm questions are designed intentionally to see how you tackle an uncommon problem or even an unfair situation and to see if you have a strategy to solve it. Of course, a candidate invited for front-end position at a decent company knows how to tackle his common tasks regardless of how complex they are in comparison.

However, that is definitely not true about all interviews. Many companies just copy these interview formats without understanding what is the actual idea behind them. Or how to facilitate these interviews correctly with different candidates from different cultures in different situations.

But you shouldn't go to interviews with this assumption. I'm sure at least one of those BigCorps had a professional recruiter.

After all, hiring a professional recruiter is as hard as hiring a good software engineer.