Really senior level is about talking to people; “Knowing the ecosystem well” (if by that you mean a specific tech stack) is almost irrelevant. Senior is more about solving the right problem than solving the problem “right”

And then you end up re-inventing the wheel, setting up servers and spending more on maintenance and development because even though your entire company is already on AWS, you didn’t know you could just click a button and make that entire part of the product someone else’s problem.....

Come on. Even highschool kids know that AWS exists, that doesn't make you "senior". How did you go from "Knowing an ecosystem well on a senior level won’t happen in a few weeks." to an example of someone reinventing the wheel? That's absolutely an example of non-senior behavior. But I was talking about e.g. someone that doesn't know Spring, or Angular - it seemed to me you were saying "can't hire a non-Spring-expert as senior if we're using Spring and he doesn't know it".

There is a difference between “knowing it exists” and knowing what it can do. No, despite what a bunch of old school netops guys who watched an ACloudGuru video and now can click around and duplicate their on prem infrastructure on AWS (and cost more) think, it’s much more than just hosting VMs.

And you kind of proved my point....

If you don’t know the wheel exists, you don’t know you’re reinventing it.

Look, I don't even know what your point is. I thought you were claiming "you can't/shouldn't hire someone who doesn't know well the technologies that you currently use". If it's not that, then don't mind me, I was debating something else/ I misunderstood your point.

That’s exactly what I’m saying, in my example the old school netops guys who didn’t know anything about the “tech stack” in this case AWS, ended up designing horrible, inefficient solutions because they were learning on the job. They could have been “senior network engineers” because they spent years managing a colo. But, they definitely weren’t as efficient as someone who had built real world solutions on AWS.

The linked article actually mentions that ("there are people with title 'senior' that can't do fizzbuzz"). So the fact that some "senior network engineers" did something stupid doesn't prove your point or invalidate the article in any way.

There's a big difference between not having experience with the <framework_du_jour>, and not knowing foundational technologies. E.g. there's a good chance Jeff Dean doesn't have much experience with most of AWS technologies, but there's no reason to believe it would take him more than a few weeks to get up-to-speed with them if he'd really need to. Not on the "expert" level, mind you - but enough to not make big mistakes.

I agree the problems you're describing are real and important to select for, but just requiring agile experience won't help you there. Lots of people practice a weird form of agile development, where they go through all the motions of fast iteration, but almost all tasks consist of non-negotiable internal dependencies and not value delivered to a customer.

I'd argue a similar thing is true for tech stacks. If there's some correlation between knowledge of all the fiddly bits of C++ and ability to write clean, performant systems-level code, I've yet to see it.

> almost all tasks consist of non-negotiable internal dependencies and not value delivered to a customer

It’s especially nice when you realize that as soon as you’ve completed all the non-negotiable features, a bunch of other things magically becomes non-negotiable.