I could present you two options:
1) I just hire you after a 30 minute chat. 50% you don't work out, and we fire you after 30 days.
2) We have a longer interview. We whiteboard. We take home test. We whiteboard some more. 90% chance that you don't get fired after 30 days.
Which would you prefer? As a business owner, I am happy to just try people I don't know well - IFF they are willing to accept that there is a very good chance they are fired within the first 30 days.
There is such a huge range in developers. The haves vs the have-nots can be a 100x different productivity difference. I really want to try to tease that difference out. It is really really hard.
That is how it works in other fields. One of our managers asked his friend that owns a body shop how he finds good employees. He basically has a chat with them, feels them out, then hires them. If they don't work out he hires someone else. Perhaps it shouldn't be as stigmatic as "firing" after 30 days but you have instead hired someone on a 30 day contract with option to hire permanently. If they don't work out, that option is not exercised and that person is free to go try somewhere else. I can tell pretty quickly from chatting with a developer if they are a total fraud. I can't tell really quickly who will become a great dev, I just know when someone has the chops to have potential.
That's the way it used to be done and I think we should go back to doing that. Read the resume, ask some questions about the resume, 30 minutes to an hour full interview, done.
You get hired on, put on a probationary period, if they don't work out, fire them.
Personally, that's my preference. If I don't think I can do the job I'll know after a 30 minute chat.
In other words, I think there is far more than 50% chance that things work out after 30 days and far less than 50% chance that I impress 6 interviewers.
Interesting idea. If you fire fast enough it may not actually cost that much more money to a business to hire a bit more as long as you fire the bad ones fast.
But a 400% increase in that you find some sort of excuse not to hire me and I won't even get hired in the first place. Your percentages only make #2 more attractive if there's a more-or-less equal chance of being hired both ways.
I suspect many people would rather do 10 interviews and then get 1 job they keep for a year+ compared to 2 interviews and a 50% chance the job that hire them, fires them in 30 days. But I could be wrong, mostly basing on what I would want.
Why did the industry seem to forget this?
I would not leave a w2 job for a contract job. Nor would any good developer I know.
This is why the industry "forgets" it. It's not that attractive to a good candidate.
Wow, 8 jobs last year? Busy life?
If you want to do that by way of an open source portfolio, sure. But not everyone has open source contributions, so then I would need some other process for acquiring a work sample.
I have seen many people here say you should hire people on a contract basis for a few days/a week. I don't know what it's like doing that in the US, but for the UK market that sounds like a ton of administrative overhead for both parties to take on in order to establish if they are even a good fit.