It depends. There are people who's core skill is that they are amazing at learning generalizable lessons about approaching new terrain. They have a toolkit of methods that allow them to move into new territory and quickly gain competency, while avoiding most of the 'newbie' mistakes (or making them on the weekend on their own time).

Other people excel at going deep on specificity. They know every detail and arcane quirk about THIS specific language/build system/toolchain.

Both of these traits are desirable, but they will be great at slightly different things and under slightly different circumstances.

> while avoiding most of the 'newbie' mistakes (or making them on the weekend on their own time).

Why would one wait to make mistakes on their own time?

Well, let me clarify. It's not something that employers should expect from employees.

But it is a trait I notice in a lot of highly competent folk who are high achievers. They'll see something coming on the roadmap that they feel like they want to prep/educate themselves on, and then they will noodle on it for an hour or two when they get a chance. By the time it comes time to implement it 'for real', they have already gotten most of the learning curve out of the way.

And you are correct. The issue is that there are very people who have walked this floor already, and many are already in the building (company) walking the floor. So, if you can find people who have already walked this floor, great, they may be better.

But, if you want access to a larger pool, then the next best is people who:

1) know how to walk and have been walking for years, and

2) have walked on many floors so that you can have confidence that they can walk this particular floor.

Sometimes the learning curve is so high, that you would rather pay extra for upfront experience.

I imagine there must be roles in the programming world that are specialised enough for this to be true. However, at least in my own experience, it is mostly general programming ability and/or domain-specific knowledge that set one developer apart from another in the speed and quality of their work. Both of those take time to acquire and have value accordingly, but they are highly transferrable across specific tools. Soft skills also matter alongside the technical ones, and much more so as seniority increases, but it’s the same story there. I can’t immediately think of a field of programming where hands-on knowledge of specific technologies matters more than these other factors.