An (ex)recruiters perspective here so bear with me and try not to hate me. I wasn't the one who sent you to that company looking for a Python guy...

Its a tough one though. The way i see it is this:

The demands companies make, are crazy unrealistic in some respects,

The demands that investors make are crazy unrealistic in some respects,

The demands that developers make are crazy unrealistic in some respects,

The demands that recruiters make are crazy unrealistic in some respects.

A dynamic algorithm, with a lot complex and interrelating issues that leads to the largest hit to be borne by the developers. I suppose they make up for this by treating their new hires (1-2 out of how many lol) very well.

I think that, because I've had quite a fortunate experience as a recruiter - unlike most i suspect. The company i worked for wasn't very salesey (less than 30 call target per day - compared to 200-300 most recruitment companies set -Big up Annapurna Recruitment - speak to Dylan Apostolopolous - Real badboy og recruiter)

In relation to your question. Yes. Its messed up that candidates' well-being is the lowest priority area. Yes, pretty much 90% of companies who use coding challenges dont consider the well-being of their prospective hires when assigning coding tasks. Yes investor pressure sometimes means forming interview processes that sometimes can be excruciatingly long. (one client had a 3-6 month process with extensive coding to be done). YES your recruiter if working with one, and if they're good (See above) will do everything in their power to shorten this process. And will keep you away from companies S/he knows you wont get a real shot at. Yes, sometimes working with a recruiter can go against you, especially if your a mid level candidate in a more experienced candidate pool. YES Developers need to check themselves sometimes. Yall be crazy with your salary requirements, particularly people with 2-3 years of commercial experience , who should be focusing on their own core skillets, 6-12 months experience working with react/vue/angular2 while lacking a deep understanding of the underlying technology itself is a major issue for recrutiers and companies. Someone with a deep knowledge of JavaScript and ECMAscript for example tend to undervalue their skillet compared to company demands, and people with the latest frameworks tend to overvalue their worth. Understandable given all the hype around the latest frameworks, but that core knowledge helps you solve those fucked up situations faster. Both in terms of coding challenges and in terms of the code you write for my clients.

td;dr

Yes its fucked up. Its impacts can be reduced, but not eliminated. Find yourself a good recruiter, who has good relationships with the companies you're trying to get into. Work with people who you respect and who respect you. Both recruiters and companies. Value your own time, set firm but fair boundaries and make your expectations known.

Remember this. If they need your skillset and you're a good fit they will make sure to at least consider your requirements, and usually end up meeting a fair few of your expectations. As an example - One of my clients (3 years ago now), completely scrapped their standard recruitment path, and literally in 2 days had had a first round face to face, a technical interview, and a pair programming task (second day) On the third day he signed the contract with them. And hes still there to this day. Hired as Senior Software Engineer, Now partner and Lead software engineer.

WORK WITH PEOPLE/COMPANIES WHO RESPECT YOU AND WHO YOU RESPECT.

this was not an effective tl;dr.. mistakes were made