Apparently it was 50 days:

https://pipiscrew.github.io/posts/why-window/

I grew up with Windows and I constantly had to fix shit just for my own casual use, the biggest barrier to moving to Linux is about learning a new OS from scratch, we already go through that learning curve with Windows normally so we forget how much time and effort it took us just to understand the system well.

That aside, I'd argue that for most productive work that doesn't require proprietary software, you also don't need to understand Linux that well to be productive. You just need to know how to log in, launch whatever you need, and then turn it off before going home. The biggest reason why we can't just make people switch overnight is that they're probably used to proprietary software that just won't work well on Linux, like Adobe or Microsoft Office. If you train your personal to first switch to FOSS alternative, when you do make the switch to Linux the learning curve for what they need to do is small and they won't be as intimidated. But now, if you're talking about how their years of learning Word or Excel or Photoshop doesn't translate 1:1 because of different UI and behavior, they'll be very uncomfortable and less productive when they switch.

Things inevitably go wrong no matter what system or software in general you use, we're just used at tolerating it when it's something we know and use already, but there's no reason why we should think Linux or FOSS software has to be strictly much more stable than its counterparts, as long as they're good enough for the person or the use case, it's already good enough to switch, with the caveat that you should never switch everything at once, but rather first switch your productive software, retrain to feel confident in it, and then switch to Linux. That way you'll not even remember you're running Linux after a few weeks, other than when you see the login screen or something.