Modern macOS is a significant counterexample to that claim. Most of it is janky. Zooming and dezooming the Finder is not something a 2.5 years old MacBook Air (€1200) can keep up with smoothly, for instance. Opening a Save dialog takes over 3 seconds, and expanding/collapsing the file explorer in it is comically janky.
That's simply not true. A 2019 MacBook Air has no trouble with any of these things. If you're having trouble with these, something is seriously wrong with your computer.
Ah, I misunderstood what you were referring to. Now that I understand, I'm less surprised. For some reason I was thinking File I/O.
The Early 2020 MacBook Air is a joke from a CPU/Graphics perspective - even compared to other Intel Macs.
I still think something's wrong with your computer, as I have worked with multiple of that model and they weren't nearly this bad (even accounting for screen recording) - perhaps your cooling is worse?
