That "False Positive" that you can "quickly fix" (by firing them) is a human being. He or she may have left a job they were reasonably happy with to join your company, or even moved to another city. The experience of being fired after a few weeks will cost them money and inflict emotional pain on them (and their family, if they have one). I wouldn't want to work for a someone who had such a careless attitude toward hiring and firing people.
I would assert that's not the reason why we currently prefer false positives and don't care about false negatives. It's mostly about risk aversion and personal responsibility of the person who's doing the hiring. If you hire someone who doesn't work out, it's a failure that falls back on you. If you pass on someone amazing, nobody will ever know.
In my opinion, this is also the mechanism behind the "we just can't find enough good people" trope we hear so often. The sad truth is people who interview amazingly well don't even work out nearly as well as they hope. So instead of taking bigger risks on candidates who don't fit the risk aversion profile, they become even more conservative in the future. The climax of this pathology can be observed inside inefficient but high-profile companies who only hire top university grads so they can tell themselves "we only hire the best of the best at Acme Inc".
We're not really in danger of implementing the hiring model you criticize any time soon. But since you bring up the human cost of that hypothetical model, I disagree. Jobs are fluid to begin with, and that trend is going to intensify. It's not a problem as long as the company is generous with both relocation and employee exit procedures. Those who are not generous deserve to be called out anyway.
What seems to be becoming more common outside of that world is a trial period as a contractor, which seems to have a bit less feel-bad if it doesn't turn into full-time employment (and also usually gives you more time to search for another job if you think/know it isn't going to work out).
I can only speak for Germany, but here it's normal to have a trial period ("Probezeit") for jobs, it's specifically designed for employers and employees to find out if they can work together. Once that trial period (which can last for months) is over, there are additional protections for the employee, but you can still fire someone, it just costs more. It's not a bad deal (and I say this as someone who once had to fire an employee for what I would call malicious incompetence: we still had to pay severance, but after that both parties went on their merry way).
You can separate doers from tellers by how they talk about the work and how they (non-verbally) react to certain questions. However, separating them by creating a totally artificial and unrealistic "doing" situation, be it via role playing or coding tests, will result in a lot of false negatives.
What if someone who is amazing at their job is going through a divorce and underperforming? Would you fire the "not doer"? There is no way for you to know what's going on in one's personal life and that can impact their performance heavily.
If your tolerance is just a few weeks to fire someone it's just immoral.
>> For those of you questioning the morality of fast iteration of new hires please consider the alternative: we deny people opportunity for fear they won’t succeed or we keep people in roles where they won’t be successful. This creates walls around (and within) organizations. Let’s welcome those who want to join us. Let’s give them as much as opportunity as we can. And let’s quickly tell them if they will have more opportunity elsewhere. As long as we do it helpfully and respectfully (which we always will), helping people sort themselves into and out of eShares is good for all involved.
The author had that covered. It is not calling for simply throwing people out like the trash because they underperform for a few weeks.