I was an employer for a decade in the 90s and I didn't think to haze any candidates or demand huge amounts of their time on speculation: I wanted honest people who were great problem solvers; you know them when you meet them. The first clue is they know about a lot of things outside of the field you are working in as well, this shows up as a very visibly and broadly capable person, making them notably self-reliant. Everyone I hired got up to speed and stayed until well after we were acquired.
As for my opinion on Agile: creating a management system to corral people without these skills doesn't magically create these skills for you in the aggregate; it might be more robust to the influence of one individual but that is a side effect of the real goal of hiring from a much broader pool, and ensuring that nobody is overly critical at the cost of headcount and ironically, agility in the business world to quickly follow opportunities.