do people really care if a site takes 3 seconds to load instead of 1 second? Yes. It has a measurable, statistically significant impact on sales. It's reported

do people really care if a site takes 3 seconds to load instead of 1 second? Yes. It has a measurable, statistically significant impact on sales. It's reported by users. It's even an issue for you because you say "If the site hasn't loaded any content I can read after 5 seconds or so..." I doubt you're measuring that. You're using a gut feel, finger in the air measure of 5 seconds. A "This site feels slow!" judgement. For a lot of people their threshold is 3s rather than 5s. That's compounded if the site is something you'd load several times a day. the /only/ thing I did for our work site was to strip down the JS/CSS to what is actually needed, compress the images (and serve webp as well) ... and that was it. That's a lot more than many devs would do if CWV or Lighthouse wasn't giving them a number to judge their effort by. It's all you really need to do for most sites. HTML and CSS are fast. It's only once you move into web apps and super-highend complex brochure sites that the advice from sites like csswizardry starts to be useful. Most people would get a site to load faster just be stripping out the things they don't need. If they aren't doing that but they are following the advice in an article like this one, and it makes their site faster anyway, that's still a win for the users.