This phrasing may sound like entitlement, but try turning it around. Most of the people who will turn down a homework assignment are the ones who can afford to do so, because they already have a good job or know they can find one. Is that really the first filter you want on your candidate pipeline?
I have never seen a job posting I was sufficiently interested in to put in 4 hours with no investment from the company.
I have, and it's how I got the job I have now, which is by far the best job I've had.
Regardless, if you have a good job already, why apply to any position you're not particularly interested in and that you wouldn't spend four hours trying to get?
Because they contacted me and offered me to participate in the
recruitment process, and while I don't look for a job, I'm not against
checking where this can take us?
I've never taken a job I've applied to myself. That is, they were the ones who approached me (some more directly than others[1])
Why would I spend any of my already very limited time if they didn't make sure the process is streamlined?
Also, I don't think it's uncommon to like what a company does and being interested without yet knowing if you're interested enough to put the time aside - most company sites and job descriptions are much too generic and vague, so I'd want to talk to some employees first (remember, interviews are two way conversations). So I might not know if I'm interested enough at the time of application, just that I might be.
[1] for my current job, the interview process was essentially them trying to persuade me to join them, and my previous job I was actively looking for a job and someone I know at the company said I should apply. My "application" consisted of telling him "ok set up an interview"
I think it is worth seeing what's out there even if you're happy. Maybe there's something better!
The standard process where the first two steps are some ordering of a 1-hour interview with someone technical and a chat with a recruiter is perfect for this. With minimal effort (maybe 90 minutes) you find out whether they're interested in you at all, and get to ask both a technical person and a recruiter about the job.
The big time investment typically comes later, and I can easily bail if I decide it isn't going to be a compelling offer. I've done this quite a bit.
I'm glad the homework process worked for you, but my point that it doesn't seem like a good idea for the company stands. If the first thing you do is filter based on how badly applicants need a job, you're losing a significant portion of the best people right off the bat.
I have never seen a job posting I was sufficiently interested in to put in 4 hours with no investment from the company.