OSs today do a lot more than 20 years ago at about the same speed as 20 years ago.
Now, we can debate if all the extras are necessary, but that seems like a different debate than speed.
I would venture to guess that you will not find anyone whose experience with Windows 2000 included any slowness comparable to what we see today, if they got it on a new PC of the time or if they installed it themselves on a newish PC of the time. It’s tempting to blame input and display latency on the increased amount of work an OS does versus wherever we happen to sit on the curve of Moore’s law, but that discounts the fact that the values, priorities, and abilities of the engineers and designers involved in OS development might have changed.
This is the sort of thing that can be tested and measured. I’d wager if you benchmark a good-spec twenty year old PC and any Windows 11 PC on common user tasks in the UI, the twenty year old machine will be faster while using a higher percentage of its CPU time performing the simple tasks you’re testing against. It’s more or less impossible to use a significant fraction of the CPU’s time dragging the mouse pointer around and opening and closing menus, or even opening and closing normal user apps, on a modern desktop PC, as you might very well see on the old one, so one might want to contemplate why the new PC’s UI has so much latency built in compared to the old one…
(I remember 20 years ago)
Already then, it didn't seem like dragging things around would eat a significant amount of CPU. I started a bunch of AVI videos playing at the same time, while dragging windows around, and everything was smooth.
Watching videos isn’t a great test of what we’re talking about, but the “everything else” involved in getting to them, opening them and navigating them might be revelatory?
People forget that a modern computer has such a large screen the frame buffer would barely fit in the memory of these old computers.
It’s a lot of work to manipulate all these pixels and it requires much larger assets as well.
But the NT 4 desktop, before the bloated sluggish abomination of Active Desktop™®, was the high point.
And NT 4 was significantly more sluggish than NT 3.51, despite the mistake of moving the GDI into the kernel in an attempt to improve performance.
2K with Active Desktop removed would be ideal, but I don't think it's possible.
Slack is obviously a pathological example, but it illustrates what’s feeling more and more common in modern GUI applications.
Probably not sluggish for any of that, just that some incompetent dev didn’t want to deal with the built in input control or the inconsistency between OSes so they rolled their own and coded it badly.
Number of times I’ve had to deal with devs doing things like deciding we must create a custom color picker only for them to code it and it glitches if you drag your mouse off the edge of the color wheel. Or coding their own text controls that break OS spellcheck or autocomplete and have input delay for some reason.
Just isn’t that much talent about up to the task of building inputs yet all the low talents rush to roll their own for the smallest reasons.
A lot more telemetry and other botnet you mean?