Interesting idea. I got an email from Facebook with invitations for the interview. Replied: “I can do it but i’m Letting you know, I will not spend a minute preparing for it. So, we can do it today”.

I never heard from this person again, which brings a question - is probability of passing it without putting personal time is so low it makes no point in even trying?

That's a nonsensical line of reasoning. Hard interviews don't reduce salaries, they increase them. Why do you think FAANG companies pay developers 300k+/year when there are so many lower-status companies who pay <100k/year and still manage to find hires? Because the latter are willing to hire candidates who have worse resumes and less impressive interview skills that the FAANG companies consider beneath them.