Err, but why do you have to prove it for every next job?...
In reality, it's a legal way for:
1. Ageism - not many seniors are desperate enough or have a free time for Competitive Programming preps.
2. Making switching jobs harder - for every next job one has to prepare again, because nobody is using Competitive Programming stuff during real work, so you forget.
Keep in mind that CP != CS.
And CP is not everyone's cup of tea. It is a separate discipline/subject with its own trivia knowledge & tricks. CP uses Computer Science the same way as e.g. Physics or Biology use Math.
In reality, it's a legal way for:
1. Ageism - not many seniors are desperate enough or have a free time for Competitive Programming preps.
2. Making switching jobs harder - for every next job one has to prepare again, because nobody is using Competitive Programming stuff during real work, so you forget.
Keep in mind that CP != CS.
And CP is not everyone's cup of tea. It is a separate discipline/subject with its own trivia knowledge & tricks. CP uses Computer Science the same way as e.g. Physics or Biology use Math.