As somebody else who started coding in the mid 80s I feel this is one of the disconnects of the interview process: interviews evaluate you on the basis of an "80s programming model" where if you needed a red black tree library, you likely had to write it on your own.

It would be a lot more representative of today's work if you were asked: given these 3 github repos with packages that all purport to do X, which one would you pick for this set of requirements and why? and how long would it take you and a team of 3 to get it done? Then you have an hour sitting next to the interviewer that can see what you are looking at in the code, what you are googling, how you are estimating and so on.

You could be the best algorithm writer in the whole world, but these days when do you ever have the luxury to write greenfield code? It's all "let's leverage open source" and "we don't have the budget to write our own frameworks" and "why do you want to spend X months writing this, when I googled and in 5 minutes I found 8 packages that do it" and "estimate how long it would take you to do <insert fuzzily defined huge task>" etc. etc. etc.

Personally I do miss the days where I felt that all I did was coding, as opposed to putting together a collage with code found elsewhere.

I sometimes feel like doing an Ask HN about "how do you find a coding job where you actually code most of the day when you are 20 years into your career"