That is not what the person you were replying to claimed. Their claim was that the overall effect of removing jQuery was negligible, and made a persuasive argument to support it, while also acknowledging that making modest improvements to the experience of a minority of users was an admirable achievement.

What is negligible is 12 down to 11.999 seconds because you prematurely optimized

Who could disagree with that verdict over an imagined scenario? I would even go so far as to say it could be considered negligible whether or not the optimization was premature or not.

And even for "normal" users, shaving milliseconds matter. The general idea is that a UI should respond within 100ms to feel instantaneous.

9 seconds is pretty fucking far from 100ms. Far enough that I feel like shaving milliseconds off does not in fact matter to the majority of “normal” users.

According to Google research, increasing page load time from 1s to 3s increases bounce rate by 32%.

Fascinating. What does the research say about increasing the load time from 9 to 12 seconds? Those are after all the figures that are relevant to this discussion.

Performance matters, a lot. I am not living in the UK, but if I was, I would be happy to pay taxes that make government websites 25% faster.

I’m sure the UK government is thrilled that you approve of how they spend their tax revenue. But just to reiterate: We’re not talking about a 25% improvement of websites across the board. We’re talking about a 25% improvement of a specific page for a small subset of users.

And even without the performance benefits, I consider removing dependencies a good thing. jQuery was great in the IE6 days, but now that even 10 year old browsers have decent JS, it is not as important as it once was. Modern versions of jQuery don't even support IE6 anymore.

I doubt anyone disagrees with this as a general statement. Certainly it would probably be a mistake to take on jQuery as a dependency today. However, it does not cost nothing to remove jQuery from a code base that has depended on it for a long time. And the cost has to weighed against the risk and the cost, not least of which is the opportunity cost: What could the programmers tasked with removing jQuery have done with their time instead?

Developers really don't care. They will claim otherwise with great conviction, but its all posturing and bullshit. If developers did care they would measure everything and challenge popular assumptions. Instead most developers want to randomly guess at what works and instead talk about tools. That's why most pages will never come close to being vaguely fast. 9 seconds is still really slow.

My hamster mobile can achieve 0 to 60mph in under 8 seconds while a Corvette C8 takes about 2.6 seconds. Nobody gives a shit what socket wrench they used to put the tires on.

That’s my point.

It does still help of course, just at tiny fractions of the impact that Google saw.

He and Richard P. Kelisky, Director of Computing Systems for IBM's Research Division, wrote about their observations in 1979, "...each second of system response degradation leads to a similar degradation added to the user's time for the following [command]. This phenomenon seems to be related to an individual's attention span. The traditional model of a person thinking after each system response appears to be inaccurate. Instead, people seem to have a sequence of actions in mind, contained in a short-term mental memory buffer. Increases in SRT [system response time] seem to disrupt the thought processes, and this may result in having to rethink the sequence of actions to be continued."

“The Economic Value of Rapid Response Time”

https://jlelliotton.blogspot.com/p/the-economic-value-of-rap...

The thing with bounce rate is that you don't know WHY the user bounced nor did you know their intent. Typically analytics aren't even loaded yet. Sure enough I believe there to be a correlation forming as you dramatically increase page response time, but you still cannot attribute a high bounce rate to performance alone, which the often quoted line does imply.

Case in point, most of Google's properties don't even come close to their own performance guidelines.

That scale of attention span places both 9s and 12s in the exact same box: you've completely lost your user's train of thought.

Is 9s better than 12s? Obviously, yes. But that wasn't the point. My point was that there is such a thing as diminishing returns. If I were to follow your train of thought (performance absolutism), we should next optimize for WAP, if you're old enough to know what it is.