Linux

Does it matter?

Yes. Of course it matters. You just disputed an observation about relative amounts, with only a single amount to support your argument. With no point of comparison, your argument is meaningless.

But now I see you already provided an answer in an earlier comment: "multiple decades of using Windows". Compared to your "~3 years" with Linux. That doesn't refute my observation at all, now does it?

(We don't even have to consider the likelihood that you've also spent more time per year on Windows than you have on Linux, since the difference in years is so significant on its own.)

Do a Google for “how to x on Linux” and tell me you’re not instructed to enter a bunch of commands you don’t understand into a terminal

If you were to complain that googling for random people's ideas on how to solve a problem tends to yield more helpful results with the older and globally dominant desktop OS than it does with the younger one with a tiny minority desktop market share, then I might say you were right about that. But instead you wrote, "it’s just not true," about something that you're not in a position to know. That's a bit of an overreach, don't you think?

It's fine not to like a thing. It's fine not to understand a thing. But to go around condemning it as inferior based on your subjective and limited experience is unfair, and more than a little biased.

How many years do you think it should take to become familiar with the basic functions of an OS?

Hard to say, given that most of us have been using our OS of choice for long enough to no longer clearly remember how long it took us. It's complicated by the fact that so many people learn Windows as their first OS, so their expectations and habits are built around it from a young age, and those shape their approach and assumptions when trying something different. But in my family, grandma got familiar and productive with the basic functions of Linux in roughly 2-3 months. I imagine it varies a lot from person to person.